Metamerism

Things That Go Weird in the Light.

Have you ever compared two garments in a store and decided they matched, only to find that when you left the store and went out into daylight they no longer matched and instead looked quite different? Do you recall the blue & black / white & gold dress image that was an internet meme not long ago?

If so, you have seen an optical phenomenon called metamerism failure (muh TAM erizm). Strictly speaking, metamerism occurs when you see two samples match under one light source (illuminant) and not match under another.

How can this be?

Well, it comes down to the difference between how an object affects light, and the color it appears to our eyes. Objects affect light by selectively reflecting or absorbing light of different wavelengths. So an object that absorbs most blue wavelengths and reflects most red wavelengths will usually appear red to our eyes. The actual color it appears to us is dependent on the spectral composition of the light reflecting off the object.

Let's say, for example, we have two objects that each reflect red light in approximately the same way but one reflects blue light while the other absorbs it. If you put both objects under reddish lighting (and most indoor tungsten lighting falls into this range) then they may appear to be very close to the same color. As there is very little blue light falling on our objects, the difference between their blue reflectiveness is almost invisible. The red reflection is about the same so they both reflect similar wavelengths and our eyes see them as the same color!

This would not be a problem if we didn't have many different colors of lighting in everyday life.

So let's take our objects outside into mid-afternoon daylight. Sunlight at that time of day contains considerably more blue light than indoor lighting. As before, our pair of objects will reflect red light similarly but one of them will reflect a significant amount of blue light while the other absorbs it. Our eyes will see the blue light from one object combined with the red light and we would probably call the result magenta. Suddenly what we thought were two reddish objects no longer match at all!

In many ways this very phenomenon is essential to color reproduction, which we discuss below, but when colors "shift" from our expectations, clients stop paying bills, and that is a problem.

The fundamental reason for metamerism is that color is a sensation rather than a property of an object. As a result, the cones in your eyes can register the same sensation from an essentially infinite variety of combinations of different light frequencies.

Color perception basically requires four factors:

Light Source + Object + Observer + Interpreter = Perception.

Where will we see this problem in the business of digital imaging?

• Proofs and press jobs failing to match under different lighting.
• Color builds chosen for normal printing failing to match under unusual lighting. A good example of this is trade show booths and how they are lit with unusual lights in exhibit halls.
• Two prints using different technologies - such as inkjet vs photographic print - failing to match under certain lighting.
• A product shot failing to match the product in all lighting conditions.

Can color management using ICC profiles correct for this problem?

No... and yes. ICC profiles are typically built using readings referenced to D50 (5000K) lighting. That means that prints created using these profiles will look best under D50 lighting. Viewing them under any other lighting can give unpredictable results.

Most printing pigments and dyes have been carefully chosen to not conflict with each other or other pigment sets. One exception that is appearing more and more is pigmented inks for inkjet printers.

Sometimes you can measure printed or scan/camera targets with a different light source such as D65 in the calculations. This should make the print viewable optimally under D65 lighting. This is not always successful and requires the appropriate settings to be available both on the instrument and in the software.

Papers manufactured with optical brighteners are especially susceptible to color changes when lights differ in their short wavelength radiation, which can cause some papers to fluoresce.

One closely-related problem cropping up more and more often in the inkjet printing world is often (incorrectly) called metamerism.

When colorants are mixed carefully in a printer, you can achieve a smooth, neutral gray gradient from black to white. With most inkjet printers, the ink combination will include Cyan, Magenta, and Yellow inks in varying amounts along with Black ink. When properly balanced, pleasing black and white images can be printed. Many users are also experimenting with near-neutral imaging such as adding a slightly blue or sepia tone for effect.

With the fugitive nature of dye-based inks, many users are switching to pigment-based inks for the vastly improved permanence. After all, if you are printing and selling works for display, your customers tend to have the expectation that the work will last beyond 2-3 years. Pigmented inks however, can suffer from a pigment balance problem which rears its head in a similar manner to the two-sample metamerism problem.

It is important to note that this is not an expected color shift but rather a shift that appears strange to the eye.

One would expect that a gray tone viewed under D50 lighting would appear to be a warmer gray when viewed under warmer, tungsten lighting. The color balance failure we are referring to here shows up as a green or magenta cast and is noticeably different than a shift normally attributed to warmer or cooler light.

Many people incorrectly refer to this phenomenon as metamerism.

Metamerism, however, is specifically defined as a phenomenon that occurs between two samples. The ink balancing situation does not involve two samples but rather a balance of pigments in one sample.

Strictly speaking, then, it is not metamerism and the problem is more correctly referred to as Gray Balance Failure or Color Balance Failure.

After all is said and done, it is fair to say that metamerism is the enemy of digital printing, right?

Not really, no.

Metamerism, remember, is when an object matches another under a certain illuminant even though the spectral characteristics of the two objects differ. The act of balancing three or four colorants (such as CMYK inks) so they appear to be the same color as an original object is also based on metamerism.

Because of the 3-channel nature of our eyes, we can get 4 inks to appear to match a real-world object like a person's face without the spectral characteristics of the inks resembling the face much at all. This means that the print and the face affect light differently but appear to be the same color to our eyes!

This is the basis of digital imaging and printing today. It is fair to say, then, that without metamerism we would not be able to do ANY of the imaging we do today! It is only when the balance fails that we call it a problem.

Perhaps a match-failure problem should be called metamerism "failure" rather than metamerism, but this term does not seem to be used at all.

As with anything in the color management world, being aware of the problem is half the battle. Now that you know about metamerism and GBF you can consider it as a contributing factor when things don't look right.

Also, if you have no D50 lighting under which to view your prints it is possible they will never look quite right. Invest in controlled lighting for print viewing. With the many variables in digital color work that can give you problems, nailing down lighting is considered a basic requirement for print viewing as well as monitor to print matching.


Since it may be impossible to completely control the lighting conditions under which colored objects are stored, displayed, or judged, the best way to prevent metamerism is to match the object with pigments with exactly the same reflectance properties. In color matching, this precision is the goal of every colorist. However, sometimes their goal cannot be met because the pigments in a target sample submitted for matching may be inappropriate for the planned application.

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Do you have a color management question, horror story or event to share?
Email me at reilley4color@gmail.com

Measuring Color

MEASURING COLOR

While there is an art to designing for and selecting the right colors, there is definitely a color science, and that means color can be measured. Scientific measurement of color output enables greater control in the print production process.

Translating color into mathematical calculations based on data generated by measuring devices eliminates the need for a press operator to “eyeball” the press sheet to see if it looks approximately right.

Color measurement instruments are able to receive color data in the same way our eyes receive color -- by gathering and filtering light that is reflected from an object, whether that object is a flower or a sheet of paper printed with offset inks or toner.

The measurement device; however, transforms the color into a numeric value that allows us to scientifically analyze the quality of a specific color object.

There are three different devices used to measure color characteristics, and each has its role during the color workflow and production process.

These devices are colorimeters, spectrophotometers and densitometers.

Colorimeters

Colorimeters measure colors using filters to determine the nature of the color. In the world of graphic communications, colorimeters are most frequently used to calibrate output devices, including monitors, printers and even LCD projectors.

A colorimeter can sometimes be used as an alternative to a spectrophotometer, but it is not as accurate. In scientific fields the word generally refers to the device that measures the absorbance of particular wavelengths of light by a specific solution.

Colorimters are far more useful in the chemistry of color, such as formulating inks and toners, than they are in the practical color management of your print devices.

Spectrophotometers

A spectrophotometer measures wavelength reflections. A light source shines through or on the item being measured, such as a printed sheet, and a detector detects how much light has been absorbed by the area of the printed sheet being measured. This absorption is then converted into a number, which can be analyzed by a computer.

A spectrophotometer (also called spectroreflectometer or reflectometer), takes measurements in the visible region (and a little beyond) of a given color sample. If the custom of taking readings at 10 nanometers (billionth of a meter) increments is followed, the visible light range of 400-700 nm will yield 31 readings. These readings are typically used to draw the sample's spectral reflectance curve (how much it reflects, as a function of wavelength). Spectrophotometers are considered to be the most accurate technology available for measuring color characteristics.

An example of a spectrophotometer is the EFI ES-1000 spectrophotometer.

Another is the iPublish Pro 2.




Densitometers

A densitometer measures color ink or toner density. Densitometers are usually used in offset printing. Because inks are known standards, a densitometer helps in controlling the amount of ink on a page and the resulting color.

Color standards, such as the standards delivered by Pantone, include ink densities as part of the color specification.


XRite makes a fine densitometer.

BabelColor has a fun online densitometer that you can play with, or use for serious color management purposes.

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Do you have a color management question, horror story or event to share?
Email me at reilley4color@gmail.com

The Role of the RIP in Digital Color

Raster image processors (RIPs) control printing devices.

They translate, in a very direct way, the page description language of PostScript into a bitmap image, either CMYK or grayscale, including trapping, font data, formatting, kerning, color input/output profiles, bleed, imposition, metadata and legal validation. What you send to the printer gets translated into a picture the printer is capable of reproducing, and there you go.

They have become increasingly sophisticated and play a significant role in the Color management because they process files for printing on digital and offset output devices, including proofing and CTP systems as well as digital printing devices.

While you can get adequate results from a simple printer driver, which performs many of the same functions as the RIP, dedicated RIP software can offer a great deal more control, more finely grained tuning of files for fine art or production applications. RIPs can offer print queuing, batch processing, color separations, halftone screening, as well as checking for missing fonts or graphics.

An effective RIP incorporates such things as ICC-compliant color management system and profiles as well as workflow integration to deliver optimum results. It cannot operate as an isolated application with proprietary tools.

Rather, RIPs must integrate with a production environment and facilitate the exchange of color profiles among the various constituencies of the Color Management Workflow, including designers, agencies, prepress operators and print service providers.

Keep in mind that graphics creation packages allow users to create files that can be very difficult to print. Also, many designers have little in-depth knowledge about the printing process and are not aware that their designs create production issues. At a minimum, an effective RIP accommodates these complex constructs, so the final printed product closely matches the design intent.

It also widens the range of file types that can be accepted into the production process. In addition, an effective RIP should be able to handle special or spot colors and correctly process overprints and transparencies.

RIPs also concatenate variable data, pairing the context of a database expressed as a CSV (Comma Separated Value) text file with tags in a PDF file to replace the tags with variable data, whether words or pictures, based upon the values from the database.

Transparencies and variable data do not play well together, since Postscript is a layers page layout description language, and both of these items prefer to be the topmost layer in the stack, and when they have to fight it out, VDP usually wins over transparency. However, a properly tuned RIP can process these files correctly, ensuring the final PDF that goes to print is correct.

Each RIP handles color management the same way. Input color profiles are translated to L*A*B* values, which are then converted to the output color profile assigned to the RIP, and the resulting PDF file matches the output profile directly.

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Do you have a color management question, horror story or event to share?
Email me at reilley4color@gmail.com

What the Heck is Delta-E?

Measuring color on printed output makes sense, but what do you do with the data collected? Also, how do you know when you have a problem? The term Delta-E, (dE) is commonly used in discussing color management and answers these questions.

Delta-E is a single number or metric that represents the “distance” between two colors.

It helps users identify the limits of their workflows and to work within these expectations. The idea is that a dE of 1.0 is the smallest color difference the human eye can see. So any dE less than 1.0 is imperceptible.

Delta-E can help constituents in the Color work flow measure differences between a proof and the final printed product or to monitor whether or not color produced by a specific printing device has drifted. It allows us to measure how far away we are from our ideal. It also helps to remove any subjectivity from the color matching process.

It also can help users determine how effective a particular profile is for printing or proofing, how closely it matches the color original.

If difference is a number showing how 'far apart' two colors are, tolerance is the meaning of the number. Determining a tolerance number defines how much variance is acceptable depending on the printing environment, how color-critical the job is, and other factors.

It should be noted that there are a variety of Delta-E types, including DEab, DE94, DE_CMc and DE2000. It is important to be aware of which Delta-E measurement is being utilized in order to make accurate comparisons. Apples to apples, after all.

DE76 was first created in 1976, the year L*a*b* was created, and is a simple calculation to determine the distance between two colors. While the math is simple, it does suffer from some limitation.

One problem with dE76 is that L*a*b* itself is not perceptually uniform as its creators had intended. So different amounts of visual color shift in different color areas of L*a*b* might have the same dE76 number.

Conversely, the same amount of color shift might result in different dE76 values.

Another issue is that the eye is most sensitive to hue differences, then chroma and finally lightness and dE76 does not take this into account

DE2000 takes into account hue, lightness and chroma factors instead of being simply a raw calculation. As a result it is much more difficult to calculate. But it is also much more accurate and a better representation of how your engine is performing.

It should be noted that the human eye cannot detect differences in Delta-E below a measurement of approximately 2.2.

In environments such as laser printers, a Delta-E of 6 to 8 is perfectly satisfactory and is the level that is often achievable on laser based devices.

Most commercial printers consider a Delta-E range of 2 to 4 acceptable.

A few important points about delta-E calculations in general:

Remember, dE calculations are based on colorimetry which means they are illuminant-dependent. Don't try comparing numbers calculated from colors viewed / measured under different illuminants.

Differing dE due to illuminant is metamerism. If colors are 'adapted' to the same white point then you have a metamerism index.

Always remember that nobody accepts or rejects color because of numbers - it's the way it looks that counts.

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Do you have a color management question, horror story or event to share?
Email me at reilley4color@gmail.com

Ink & Toner

INK AND TONER

How color actually appears when produced on an offset or digital press is affected by several factors, including the printing plate quality produced from the original file or master for offset printing, the press settings, the paper, or other substrate, ink or toner types that are used to produce the job; and even the environment or condition of the press and the press area, regardless whether digital or offset.

Let's take a closer look at Ink and Toner

Ink

The press operator has significant influence on the way colors are produced in print. Factors include increasing or decreasing the amount of ink that is applied to the page for offset, and shifting the CMYK balance — that is, increasing the amount of one or more of the primary colors independent of each other — for either offset or digital devices.

By taking these actions, the press operator can match the proof -- fine tuning the press during print production to produce a printed sheet equivalent to the contract proof that the customer has approved or will approve. Offset and Web Operators can match printed sheets to proofs with a visual examination or by using color measurement tools.

It is important to understand that color matching between proofs and printed sheets may not always be 100% accurate, even if all of these steps are employed. Using measurement tools gives greater consistency than visual inspection, no matter how skilled the operator.

Did you know that 7-10% of all males  and 0.5-1% of all females have a color deficiency, which is why using instruments to measure color is more accurate than "eyeballing" color.

Here is free color vision test online you can use to showcase the point.

This situation is due to the fact that, especially in the offset environment, the proofing device uses different inks and may be printing on different paper than is actually used in final production at the offset press.

For example, more intense colors can be produced on a high-quality coated paper than on a less expensive, uncoated paper.

If a proof is produced on coated stock with the final product produced on uncoated stock, it may be difficult to obtain an accurate color match at press time. The more accurately the final printing conditions are met in the proof, the greater chance for success the entire print enjoys.

The density with which the ink is applied to the paper can be measured with a densitometer, which allows the press operator to deliver consistency, from sheet to sheet, and even job to job, especially if a job is being reprinted. A spectrophotometer is used to measure color accuracy.

While there are consistent standards that apply to offset inks, there are inconsistent standards relative to inkjet inks that are provided by different suppliers. This will be discussed further in the future.

Toner

This extremely fine powder, which has a consistency akin to talcum powder, gains an electric charge when it comes in contact with the copier's rotating drum. The copier's laser beam then removes the charge from the previously charged areas of the drum, leaving certain areas free to be coated with toner. The drum rolls over a sheet of paper with certain areas coated in toner, creating an image. Various mixed ingredients compose toner powder, in turn making up miniscule particles generally ranging in size from five to 15 microns---a millionth of a meter---around.

Read more : http://www.ehow.com/list_6757488_ingredients-copier-toner_.html

This extremely fine powder, which has a consistency akin to talcum powder, gains an electric charge when it comes in contact with the copier's rotating drum. The copier's laser beam then removes the charge from the previously charged areas of the drum, leaving certain areas free to be coated with toner. The drum rolls over a sheet of paper with certain areas coated in toner, creating an image. Various mixed ingredients compose toner powder, in turn making up miniscule particles generally ranging in size from five to 15 microns - a millionth of a meter - in size.

This extremely fine powder, which has a consistency akin to talcum powder, gains an electric charge when it comes in contact with the copier's rotating drum. The copier's laser beam then removes the charge from the previously charged areas of the drum, leaving certain areas free to be coated with toner. The drum rolls over a sheet of paper with certain areas coated in toner, creating an image. Various mixed ingredients compose toner powder, in turn making up miniscule particles generally ranging in size from five to 15 microns---a millionth of a meter---around.

Read more : http://www.ehow.com/list_6757488_ingredients-copier-toner_.html

This extremely fine powder, which has a consistency akin to talcum powder, gains an electric charge when it comes in contact with the copier's rotating drum. The copier's laser beam then removes the charge from the previously charged areas of the drum, leaving certain areas free to be coated with toner. The drum rolls over a sheet of paper with certain areas coated in toner, creating an image. Various mixed ingredients compose toner powder, in turn making up miniscule particles generally ranging in size from five to 15 microns---a millionth of a meter---around.

Read more : http://www.ehow.com/list_6757488_ingredients-copier-toner_.html

This extremely fine powder, which has a consistency akin to talcum powder, gains an electric charge when it comes in contact with the copier's rotating drum. The copier's laser beam then removes the charge from the previously charged areas of the drum, leaving certain areas free to be coated with toner. The drum rolls over a sheet of paper with certain areas coated in toner, creating an image. Various mixed ingredients compose toner powder, in turn making up miniscule particles generally ranging in size from five to 15 microns---a millionth of a meter---around.

Read more : http://www.ehow.com/list_6757488_ingredients-copier-toner_.html

This extremely fine powder, which has a consistency akin to talcum powder, gains an electric charge when it comes in contact with the copier's rotating drum. The copier's laser beam then removes the charge from the previously charged areas of the drum, leaving certain areas free to be coated with toner. The drum rolls over a sheet of paper with certain areas coated in toner, creating an image. Various mixed ingredients compose toner powder, in turn making up miniscule particles generally ranging in size from five to 15 microns---a millionth of a meter---around.

Read more : http://www.ehow.com/list_6757488_ingredients-copier-toner_.html

This extremely fine powder, which has a consistency akin to talcum powder, gains an electric charge when it comes in contact with the copier's rotating drum. The copier's laser beam then removes the charge from the previously charged areas of the drum, leaving certain areas free to be coated with toner. The drum rolls over a sheet of paper with certain areas coated in toner, creating an image. Various mixed ingredients compose toner powder, in turn making up miniscule particles generally ranging in size from five to 15 microns---a millionth of a meter---around.

Read more : http://www.ehow.com/list_6757488_ingredients-copier-toner_.html

This extremely fine powder, which has a consistency akin to talcum powder, gains an electric charge when it comes in contact with the copier's rotating drum. The copier's laser beam then removes the charge from the previously charged areas of the drum, leaving certain areas free to be coated with toner. The drum rolls over a sheet of paper with certain areas coated in toner, creating an image. Various mixed ingredients compose toner powder, in turn making up miniscule particles generally ranging in size from five to 15 microns---a millionth of a meter---around.

Read more : http://www.ehow.com/list_6757488_ingredients-copier-toner_.html

This extremely fine powder, which has a consistency akin to talcum powder, gains an electric charge when it comes in contact with the copier's rotating drum. The copier's laser beam then removes the charge from the previously charged areas of the drum, leaving certain areas free to be coated with toner. The drum rolls over a sheet of paper with certain areas coated in toner, creating an image. Various mixed ingredients compose toner powder, in turn making up miniscule particles generally ranging in size from five to 15 microns---a millionth of a meter---around.

Read more : http://www.ehow.com/list_6757488_ingredients-copier-toner_.html

This extremely fine powder, which has a consistency akin to talcum powder, gains an electric charge when it comes in contact with the copier's rotating drum. The copier's laser beam then removes the charge from the previously charged areas of the drum, leaving certain areas free to be coated with toner. The drum rolls over a sheet of paper with certain areas coated in toner, creating an image. Various mixed ingredients compose toner powder, in turn making up miniscule particles generally ranging in size from five to 15 microns---a millionth of a meter---around.

Read more : http://www.ehow.com/list_6757488_ingredients-copier-toner_.html

This extremely fine powder, which has a consistency akin to talcum powder, gains an electric charge when it comes in contact with the copier's rotating drum. The copier's laser beam then removes the charge from the previously charged areas of the drum, leaving certain areas free to be coated with toner. The drum rolls over a sheet of paper with certain areas coated in toner, creating an image. Various mixed ingredients compose toner powder, in turn making up miniscule particles generally ranging in size from five to 15 microns---a millionth of a meter---around.

Read more : http://www.ehow.com/list_6757488_ingredients-copier-toner_.html

This extremely fine powder, which has a consistency akin to talcum powder, gains an electric charge when it comes in contact with the copier's rotating drum. The copier's laser beam then removes the charge from the previously charged areas of the drum, leaving certain areas free to be coated with toner. The drum rolls over a sheet of paper with certain areas coated in toner, creating an image. Various mixed ingredients compose toner powder, in turn making up miniscule particles generally ranging in size from five to 15 microns---a millionth of a meter---around.

Read more : http://www.ehow.com/list_6757488_ingredients-copier-toner_.html

This extremely fine powder, which has a consistency akin to talcum powder, gains an electric charge when it comes in contact with the copier's rotating drum. The copier's laser beam then removes the charge from the previously charged areas of the drum, leaving certain areas free to be coated with toner. The drum rolls over a sheet of paper with certain areas coated in toner, creating an image. Various mixed ingredients compose toner powder, in turn making up miniscule particles generally ranging in size from five to 15 microns---a millionth of a meter---around.

Read more : http://www.ehow.com/list_6757488_ingredients-copier-toner_.html

This extremely fine powder, which has a consistency akin to talcum powder, gains an electric charge when it comes in contact with the copier's rotating drum. The copier's laser beam then removes the charge from the previously charged areas of the drum, leaving certain areas free to be coated with toner. The drum rolls over a sheet of paper with certain areas coated in toner, creating an image. Various mixed ingredients compose toner powder, in turn making up miniscule particles generally ranging in size from five to 15 microns---a millionth of a meter---around.

Read more : http://www.ehow.com/list_6757488_ingredients-copier-toner_.html

This extremely fine powder, which has a consistency akin to talcum powder, gains an electric charge when it comes in contact with the copier's rotating drum. The copier's laser beam then removes the charge from the previously charged areas of the drum, leaving certain areas free to be coated with toner. The drum rolls over a sheet of paper with certain areas coated in toner, creating an image. Various mixed ingredients compose toner powder, in turn making up miniscule particles generally ranging in size from five to 15 microns---a millionth of a meter---around.

Read more : http://www.ehow.com/list_6757488_ingredients-copier-toner_.html

This extremely fine powder, which has a consistency akin to talcum powder, gains an electric charge when it comes in contact with the copier's rotating drum. The copier's laser beam then removes the charge from the previously charged areas of the drum, leaving certain areas free to be coated with toner. The drum rolls over a sheet of paper with certain areas coated in toner, creating an image. Various mixed ingredients compose toner powder, in turn making up miniscule particles generally ranging in size from five to 15 microns---a millionth of a meter---around.

Read more : http://www.ehow.com/list_6757488_ingredients-copier-toner_.html

In its early form it was a mix of carbon powder and iron oxide. Then, to improve the quality of the printout, the carbon was melt-mixed with a polymer.

Toner particles are melted by the heat of the fuser, and are thus bonded to the paper.

In earlier machines, this low-cost carbon toner was poured by the user from a bottle into a reservoir in the machine. Current machines feed directly from a sealed laser toner cartridge.

Toner results also vary from manufacturer to manufacturer or from ink batch to ink batch.

Additionally, different paper types can result in different ink absorption rates, which in turn, cause color to vary from one paper type to another. The print drivers — or the instructions that bridge the document creation software and the print hardware, allowing the desktop user to print to the device — for inkjet printers generally have an option that can be selected to specify the paper type.

This option reduces that variability. Inkjet printers are relatively stable in their ability to deliver accurate color reproduction. This stability makes it easier to build a reliable color management process across the print workflow.

As you can see, it is critical to have coordination between the creator of the original file and the various stages of job processing throughout the print workflow to ensure that the output meets the customer’s expectations.

Unfused toner is easily cleaned from most water-washable clothing. Because toner is a wax or plastic powder with a low melting temperature, it must be kept cold while cleaning.

Recycling of pre-consumer waste toner is practiced by most manufacturers. Classifying toner to the desired size distribution produces off-size rejects, but these become valuable feedstocks for the compounding operation, and are recycled this way.

Post-consumer waste toner appears primarily in the cleaning operation of the photo-printing machine.

In early printers, as much as 20 to 25% of feed toner would wind up in the cleaner sump and be discarded as waste. Improved printer efficiencies have reduced this waste stream to lower levels, although on average 13% of the toner in each cartridge is still wasted.

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Do you have a color management question, horror story or event to share?
Email me at reilley4color@gmail.com

Spot Colors

SPOT COLORS

Sometimes inks or toners are specially mixed to deliver an exact match to a specific color, rather than using CMYK inks to produce four-color process. In the offset world, ink comes pre-mixed in cans.

These special colors are called spot colors, or sometimes, Pantone colors. Pantone, Inc. developed the first color matching system in 1963. This proprietary system, called the Pantone Matching System (PMS), contains the formulas for creating and reproducing more than a thousand different “spot” colors on a CMYK device. This reason is why spot colors are sometimes referred to as PMS colors. Other color matching systems include HKS, Toyo and RAL.

It may be best to think of the Pantone library as a way to reference color, so that a person on the East coast can be reasonably sure that their printer on the West coast knows know what color they expect to see in the proof. If your Pantone swatch book is more than a couple of years old, it may not be reproducing colors correctly due to age, UV light damage, moisture, and other reasons.

In 2007, Pantone announced a new color matching system, called Goe, which consists of more than 2,000 colors. While there is some overlap between PMS and Goe, Goe does introduce a large number of new colors to the market.

If CMYK inks can be combined to create colors in a subtractive color system, you might wonder why there is a need for special spot colors. There are three key reasons special inks are used:

First, not all colors can be matched using CMYK, so they require a special spot color ink.
Secondly, it can be difficult to accurately reproduce certain color gamuts, such as saturated color. Finally, color shifts caused by mis-registration and process tolerance can occur when attempting to match a special color with CMYK inks. 

Spot colors can also be used for varnish effects, die cutting, or special effects in 5-color presses.

If the piece being printed is a full-color piece, additional spot color requires an extra printing unit on the press, or an extra pass through the press to create what would be five-color printing. That is, a four-color press has four printing units, each imaging one ink color (CMYK). To add a spot color, a fifth unit (or a five-color press) is required. Otherwise, the piece must be run through the press again to overlay the spot color. 

For offset printing, another pass through the press requires drying time (to let the first four colors dry), and complete wash-up of at least one printing unit to allow the addition of the special color. It also introduces the need to assure precise registration of the color being laid down in the second pass as it relates to the four colors that have already been printed. This process can add significant time and cost to a printing job.

For digital printers, which generally print using CMYK toner or inks, spot colors can be effectively matched using sophisticated algorithms within the RIP, which helps users manage spot colors and edit the CMYK or RGB values to better match corporate or custom colors. Even so, there are still some colors which are difficult, or even impossible, to match in the CMYK space.

When designing a printed piece, careful consideration should be given to whether or not a spot color should be specified. Quality, color accuracy, cost and the color-critical nature of the piece represent a few of these considerations. 

In some cases, it makes sense to use an alternative color that is more likely to reproduce accurately with CMYK inks. Pantone PMS and Goe systems provide Bridge Books as well as online software that help designers and printers determine how faithfully a PMS or Goe color can be reproduced, making suggestions about alternative color choices.

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PANTONE®, Goe™ and other Pantone, Inc. trademarks are the property of Pantone, Inc.

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Do you have a color management question, horror story or event to share?
Email me at reilley4color@gmail.com

Color Space

Color Space

In most cases, device-independent color definitions have three dimensions, and these dimensions make up what we call a color space. The dimensions are:

Hue: According to the American Heritage Dictionary, hue refers to a particular gradation of color such as a shade or tint, like “all the hues of the rainbow.” An individual frequency in the color spectrum. Humans are capable of discerning over 10 MILLION colors.

Saturation: This term refers to the vividness of hue or purity of a color. Intensity can be increased or decreased to suit.

Brightness or Luminance: (also called Value) The terms refer to the dimension of a color that can range from very dim (dark) to very bright (dazzling). A grayscale image is an example of an image represented with only the Luminance value.

Conventional four-color offset printing and most color digital printers use four colors – Cyan, Magenta, Yellow and Black – as subtractive primary colors to create a wide range of additional colors in what is known as four-color process. These four colors, referred to as CMYK, with “K” representing black, have long been the primary color space utilized in the world of printing. As mentioned earlier, CMY are the three primary subtractive colors, and when mixed in equal parts, in theory result in black. In reality, a dark color that is not a true black may result from less than ideal colorants, or impurities in the toner or ink components.

To economize on ink consumption and to produce deeper black tones, unsaturated and dark colors are produced by substituting black ink for the combination of cyan, magenta and yellow.

When an image is captured or created digitally — that is, scanned and captured with a digital camera, or created using desktop publishing software — it is commonly represented using red, green and blue (RGB) as this is the color language that your computer monitor requires. These colors are the additive primary colors that are mixed with light and used in displaying images on a screen. Here is a great video that shows you how to use this info to ensure your color palette will always harmonize when designing.

CMYK and RGB represent two very different color spaces. With the world’s increasing volume of digitally captured files, most of which are in RGB format, printers preparing a file for print must consider the color space in which various elements are created. Having the processes in place to convert these files as appropriate for the intended output device is equally important. To convert values obtained from an input device, such as RGB from a scanner or digital camera, into the device code values needed by an output (rendering) device, such as a CMYK printer, a transformation is needed to modify the data.

This role belongs to the ICC profile, which directs the actual color conversion produced by a color management module (CMM). The CMM uses the profiles to convert and match colors on one device’s color space to or from another device’s color space. When colors on one device’s gamut are displayed on a device with a different color gamut, the CMM attempts to minimize the perceived differences in the displayed colors between the two devices.

In general, you want to use color spaces that are as large as is practical. For example, if your printer is capable of producing output in a color space larger than sRGB, there is no reason to hobble your work by limiting output to the small sRGB gamut. If you do, you'll lose the saturated cyans and greens that can make your prints stand out.

Your applications and devices need to know what color space they are working with.

This most definitely includes your monitor. Without knowing what color space your monitor displays images in, it is impossible to accurately gauge how your images will appear in print. Calibration and profiling of your monitor is the first step towards a color managed workflow.

Most printers and all but a very few scanners or cameras either print or capture images in well-defined color spaces.

Larger color spaces contain both more colors and brighter, more saturated colors.

If your camera or scanner supports it, use a larger color space such as Adobe RGB.

Use sRGB for web graphics. This is at least in the same ballpark as most monitors. Using Adobe RGB for web images leads to washed-out looking colors in applications that are not color aware (i.e. most web browsers).

Your computer handles color differently than your monitor does, and differently than your print output requires. Your computer understands color in LAB colorspace, which we will discuss in detail later. The CMM translates from RGB to LAB and then from LAB to CMYK based upon ICC profiles. This interim colorspace is called Profile Connections Space (PCS) is either CIELAB (L*a*b*) or CIEXYZ.

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Do you have a color management question, horror story or event to share?

Email me at reilley4color@gmail.com

Color Management Definitions

DEFINITIONS

Acid Free - Acid-free papers are manufactured in an alkaline environment, which prevents the internal chemical deterioration of the paper over time. The addition of calcium carbonate as a buffer also makes the paper resistant to the effects of an external acidic environment.

Additive Color -  An additive color model involves light emitted directly from a source or illuminant of some sort. The additive reproduction process starts with black or the absence of color. Color combinations of red, green and blue (RGB) are then added to achieve the desired color. Computer monitors and televisions are the most common application of additive color.  Red, Green and Blue components of the total spectrum of light combine to create the phenomena of color.

Alteration - Any change made by the customer after copy or artwork has been given to the service bureau, separator or printer. The change could be in copy, specifications or both. Also called AA, author alteration and customer alteration.

Anodized Plate - An offset printing plate having a treated surface in order to reduce wear for extended use.

Anti-Offset Powder - Fine powder lightly sprayed over the printed surface of coated paper as sheets leave a press. Also called dust, offset powder, powder and spray powder.

Antique Paper - Roughest finish offered on offset paper.

Aqueous Coating - Coating in a water base and applied like ink by a printing press to protect and enhance the printing underneath.

Archival - Archival papers do not deteriorate (become brittle) over time and are acid-free.

Artwork - All original copy, including type, photos and illustrations, intended for printing. Also called art.

Author's Alterations (AA) - At the proofing stage, changes that the client requests to be made concerning original art provided. AAs are usually considered an additional cost to the client.

Back Up - (1) To print on the second side of a sheet already printed on one side.

                  (2) To adjust an image on one side of a sheet so that it aligns back to back with an image on the other side.

Base Art - Copy pasted up on the mounting board of a mechanical, as compared to overlay art. Also called base mechanical.

Basic Size - The standard size of sheets of paper used to calculate basis weight in the United States and Canada.

Basis Weight - In the United States and Canada, the weight, in pounds, of a ream (500 sheets) of paper cut to the basic size. Also called ream weight and substance weight (sub weight). In countries using ISO paper sizes, the weight, in grams, of one square meter of paper. Also called grammage and ream weight.

Bind - Usually in the book arena, but not exclusively, the joining of leafs or signatures together with either wire, glue or other means.

Bindery - Usually a department within a printing company responsible for collating, folding and trimming various printing projects.

Blank - Category of paperboard ranging in thickness from 15 to 48 points.

Blanket - Rubber-coated pad, mounted on a cylinder of an offset press, that receives the inked image from the plate and transfers it to the surface to be printed.

Bleed - Bleed is the excess image area outside the crop marks. Normally, at least ⅛” bleed is required. If artwork is supplied without bleed then it creates problems when trimming the final job to the finished size, and you could see a white edge due to slight guillotining inconsistencies. The only way to eliminate this when artwork has been supplied without bleed is to trim the job undersize, which is not the correct procedure.

Blind Folio - A page number not printed on the page. (In the book arena, a blank page traditionally does not print a page number.)

Blind Image - Image debossed, embossed or stamped, but not printed with ink or foil.

Blocking - Sticking together of printed sheets causing damage when the surfaces are separated.

Blueline - Prepress photographic proof made from stripped negatives where all colors show as blue images on white paper. Because “blueline” is a generic term for proofs made from a variety of materials having identical purposes and similar appearances, it may also be called a blackprint, blue, blueprint, brownline, brownprint, diazo, dieline, ozalid, position proof, silverprint, Dylux and VanDyke.

Blurb - A description of or commentary on author or book content positioned on the book jacket.

Board Paper - General term for paper over 110 lbs index, 80 lbs cover or 200 gsm that is commonly used for products such as file folders, displays and postcards. Also called paperboard.

Body - The main text of work not including the headlines.

Boiler Plate - Blocks of repetitive type used and copied over and over again.

Bond Paper - Category of paper commonly used for writing, printing and photocopying. Also called business paper, communication paper, correspondence paper and writing paper.

Book Block - Folded signatures gathered, sewn and trimmed, but not yet covered.

Book Paper - Category of paper suitable for books, magazines, catalogs, advertising and general printing needs. Book paper is divided into uncoated paper (also called offset paper), coated paper (also called art paper, enamel paper, gloss paper and slick paper) and text paper.

Border - The decorative design or rule surrounding matter on a page.

Bounce - (1) A repeating registration problem in the printing stage of production.

                (2) Customer unhappy with the results of a printing project and refuses to accept the project.

Brightness or Luminance: (also called Value) The terms refer to the dimension of a color that can range from very dim (dark) to very bright (dazzling). A grayscale image is an example of an image represented with only the Luminance value.

Bristol Paper - General term referring to paper 6 points or thicker with basis weight between 90 lbs and 200 lbs (200-500 gsm). Used for products such as index cards, file folders and displays.

Broadside - The term used to indicate work printed on one side of a large sheet of paper.

Broken Carton - Carton of paper from which some of the sheets have been sold. Also called less carton.

Bronzing - The effect produced by dusting wet ink after printing and using a metallic powder.

Build A Color - To overlap two or more screen tints to create a new color. Such an overlap is called a build, color build, stacked screen build or tint build.

Bulk - Thickness of paper relative to its basic weight.

Bullet - A dot or similar marking to emphasize text.

Burst Perfect Bind - To bind by forcing glue into notches along the spines of gathered signatures before affixing a paper cover. Also called burst bind, notch bind and slotted bind.

Butt Register - Register where ink colors meet precisely without overlapping or allowing space between, as compared to lap register. Also called butt fit and kiss register.

Buy Out - To subcontract for a service that is closely related to the business of the organization. Also called farm out. Work that is bought out or farmed out is sometimes called outwork or referred to as being out of house.

C1S & C2S - Abbreviations for coated one side and coated two sides.

Calendar - To make the surface of paper smooth by pressing it between rollers during manufacturing.

Calibration - it means to check, adjust, or systematically standardize a device’s performance.

Caliper - (1) Thickness of paper or other substrate expressed in thousandths of an inch (mils or points), pages per inch (ppi), thousandths of a millimeter (microns) or pages per centimeter (ppc).

               (2) Device on a sheetfed press that detects double sheets or on a binding machine that detects missing signatures or inserts.

Camera-Ready Copy - Mechanicals, photographs and art fully prepared for reproduction according to the technical requirements of the printing process being used. Also called finished art and reproduction copy.

Candela - Measurement of the brightness of light. Luminance is described as Candelas per square meter (cd/m^2) The luminous intensity equal to 1/60 of the luminous intensity per square centimeter of a blackbody radiating at the temperature of solidification of platinum (2,046°K). This also where the term candle power came from.

Carbon Neutral - To be carbon neutral an entity must have its carbon emissions calculated, reduced where possible and offset through the purchase of real, verified and additional carbon offset credits.Business using a process camera to make photostats, halftones, plates and other elements for printing. Also called prep service and trade camera service.

Carbonless Paper - Paper coated with chemicals that enable transfer of images from one sheet to another with pressure from writing or typing.

Carload - Selling unit of paper that may weigh anywhere from 20,000 to 100,000 pounds (9,090 to 45,454 kilos), depending on which mill or merchant uses the term. Abbreviated CL.

Carton - Selling unit of paper weighing approximately 150 pounds (60 kilos). A carton can contain anywhere from 500 to 5,000 sheets, depending on the size of sheets and their basis weight.

Case - Covers and spine that, as a unit, enclose the pages of a casebound book.

Case Bind - To bind using glue to hold signatures to a case made of binder board covered with fabric, plastic or leather. Also called cloth bind, edition bind, hard bind and hard cover.

Cast-Coated Paper - High-gloss, coated paper made by pressing the paper against a polished, hot, metal drum while the coating is still wet.

Catalog Paper - Coated paper rated #4 or #5 with basis weight from 35 lbs to 50 lbs (50 to 75 gsm) commonly used for catalogs and magazines.

CGATS.17-x (x= current year) is THE standard text file format for exchanging color measurement data. This standard text format (the ASCII version is the most common) is the format accepted by most color measurement and profiling applications.

It consists of a Preamble section containing originator information, keyword definitions, etc and then one or more data sections, each consisting of header and data subsections. The header subsection is where the BEGIN_DATA_FORMAT and END_DATA_FORMAT delimiters define the actual data types / units contained in the following tables. The data subsection contains the BEGIN_DATA and END_DATA delimiters which contain the actual color information in tabular form.

CGATS.17 text files can contain device (RGB, CMYK, etc), colorimetric (Lab, XYZ, etc), densitometric, spectral, naming and other information so it is a fairly comprehensive storage and exchange format.

The CGATS.17-200x (x for year) document is available for purchase at a nominal fee so we are unable to directly link to it from this ColorWiki article.

You may purchase the document here:

ANSI Webstore

CGATS Standards at NPES

Chain Dot - (1) Alternate term for elliptical dot, so called because midtone dots touch at two points, so look like links in a chain.

                     (2) Generic term for any midtone dots whose corners touch.

Chain Lines - (1) Widely spaced lines in laid paper.

                        (2) Blemishes on printed images caused by tracking.

Chalking - Deterioration of a printed image caused by ink that absorbs into paper too fast or has long exposure to sun and wind, making printed images look dusty. Also called crocking.

Check Copy - (1) Production copy of a publication verified by the customer as printed, finished and bound correctly.

                        (2) One set of gathered book signatures approved by the customer as ready for binding.

Choke - Technique of slightly reducing the size of an image to create a hairline trap or to outline. Also called shrink and skinny.

Chrome - Strength of a color as compared to how close it seems to neutral gray. Also called depth, intensity, purity and saturation.

CIE - Committee Internationale de l'Eclairage (The International Commission on Lighting)

The body responsible for recommendations on photometry and colorimetry. The CIE has defined several "color spaces" that describe the range of visible colors in unambiguous numerical terms.

Close Up - A mark used to indicate closing space between characters or words. Usually used in proofing stages.

CMYK - Abbreviation for cyan, magenta, yellow and key (black), the four process colors.

Coarse Screen - Halftone screen with ruling of 65, 85 or 100 lines per inch (26, 34 or 40 lines per centimeter).

Coated Paper - Paper with a coating of clay and other substances that improves reflectivity and ink holdout. Mills produce coated paper in the four major categories cast, gloss, dull and matte.

Collate - To organize printed matter in a specific order as requested.

Collating Marks - Mostly in the book arena, specific marks on the back of signatures indicating exact position in the collating stage.

Color Balance - Refers to amounts of process colors that simulate the colors of the original scene or photograph.

Color Blanks - Press sheets printed with photos or illustrations, but without type. Also called shells.

Color Break - In multicolor printing, the point, line or space at which one ink color stops and another begins. Also called break for color.

Color Cast - Unwanted color affecting an entire image or portion of an image.

Color Control Bar - Strip of small blocks of color on a proof or press sheet to help evaluate features such as density and dot gain. Also called color bar, color guide and standard offset color bar.

Color Correct - To adjust the relationship among the process colors to achieve desirable colors.

Color Curves - Instructions in computer software that allow users to change or correct colors. Also called HLS and HVS tables.

Color Electronic Prepress Systems - Computer, scanner, printer and other hardware and software designed for image assembly, color correction, retouching and output onto proofing materials, film or printing plates. Abbreviated CEPS.

Color Gamut - The subset of colors which can be accurately represented in a given circumstance, such as within a given color space or by a certain output device. The extent of the three dimensions of the colorspace. This term is also used for the map of this space, showing HSL limits.

Color Key - Brand name for an overlay color proof. Sometimes used as a generic term for any overlay color proof.

Color Management - The communication of the associated data required for unambiguous interpretation of color content data, and application of color data conversions as required to produce the intended reproductions.

Color Management Module - A color management module (CMM) does color conversation. It is embedded in graphic arts applications, software, operating system and hardware driver. It uses the profiles to convert and match colors in a given color space on a given device to or from another color space or device via the LAB color space.

Colorimeter - Colorimeters are devices that can identify or characterize colors by measuring relative light frequencies.

Color Model - Way of categorizing and describing the infinite array of colors found in nature.

Color Separation - (1) Technique of using a camera, scanner or computer to divide continuous-tone color images into four halftone negatives.

                                (2) The product resulting from color separating and subsequent four-color process printing. Also called separation.

Color Sequence - Order in which inks are printed. Also called laydown sequence and rotation.

Color Shift - Change in image color resulting from changes in register, ink densities or dot gain during four-color process printing.

Color Transparency - Film (transparent) used as art to perform color separations.

Comb Bind - To bind by inserting the teeth of a flexible plastic comb through holes punched along the edge of a stack of paper. Also called plastic bind and GBC bind (a brand name).

Commercial Printer - Printer producing a wide range of products such as announcements, brochures, posters, booklets, stationery, business forms, books and magazines. Also called job printer because each job is different.

Complementary Flat(s) - The second or additional flat(s) used when making composite film or for two or more burns on one printing plate.

Composite Art - Mechanical on which copy for reproduction in all colors appears on only one surface, not separated onto overlays. Composite art has a tissue overlay with instructions that indicate color breaks.

Composite Film - Film made by combining images from two or more pieces of working film onto one film for making one plate.

Composite Proof - Proof of color separations in position with graphics and type. Also called final proof, imposition proof and stripping proof.

Composition - (1) In typography, the assembly of typographic elements, such as words and paragraphs, into pages ready for printing.

                         (2) In graphic design, the arrangement of type, graphics and other elements on the page.

Comprehensive Dummy - Simulation of a printed piece complete with type, graphics and colors. Also called color comprehensive and comp.

Condition - To keep paper in the pressroom for a few hours or days before printing so that its moisture level and temperature equal that in the pressroom. Also called cure, mature and season.

Conductivity - The electrical property of a sheet of paper that enables it to attract charged toner. Low conductivity can result in poor image quality in digital system.

Contact Platemaker - Device with lights, timing mechanism and vacuum frame used to make contact prints, duplicate film, proofs and plates. Also called platemaker and vacuum frame.

Continuous-Tone Copy - All photographs and those illustrations having a range of shades not made up of dots, as compared to line copy or halftones. Abbreviated contone.

Contrast - The degree of tones in an image ranging from highlight to shadow.

Converter - Business that makes products such as boxes, bags, envelopes and displays.

Copyboard - Surface or frame on a process camera that holds copy in position to be photographed.

Cover - Thick paper that protects a publication and advertises its title. Parts of covers are often described as follows: Cover 1=outside front; Cover 2=inside front; Cover 3=inside back; Cover 4=outside back.

Coverage - Extent to which ink covers the surface of a substrate. Ink coverage is usually expressed as light, medium or heavy.

Cover Paper - Category of thick paper used for products such as posters, menus, folders and covers of paperback books.

Crash - Coarse cloth embedded in the glue along the spine of a book to increase strength of binding. Also called gauze, mull and scrim.

Creep - Phenomenon of middle pages of a folded signature extending slightly beyond outside pages. Also called feathering, outpush, push out and thrust. See also Shingling.

Crop Marks - Marks on each corner of the sheet indicating where the sheet will be guillotined to the finished size. Also called trim marks or cut marks.

Crossover - Type or art that continues from one page of a book or magazine across the gutter to the opposite page. Also called bridge, gutter bleed and gutter jump.

CTP - This term means computer to plate. It is the generation of a printing plate directly from a digital file, eliminating the need to use film in the plate production process.

Cure - To dry inks, varnishes or other coatings after printing to ensure good adhesion and prevent setoff.

Customer Service Representative - Employee of a printer, service bureau, separator or other business who coordinates projects and keeps customers informed. Abbreviated CSR.

Cutoff - Circumference of the impression cylinder of a web press, therefore also the length of the printed sheet that the press cuts from the roll of paper.

Cut Marks - Marks on each corner of the sheet indicating where the sheet will be guillotined to the finished size. Also called crop marks or trim marks.

Cut Sizes - Paper sizes used with office machines and small presses.

Cutting Machine - A machine that cuts stacks of paper to desired sizes. The machine can also be used in scoring or creasing.

Cutting Die - Usually a custom ordered item to trim specific and unusual sized printing projects.

CWT - Abbreviation for hundredweight using the Roman numeral C=100.

Cyan - One of the four process colors. Also known as process blue.

Data Compression - Technique of reducing the amount of storage required to hold a digital file to reduce the disk space the file requires and allow it to be processed or transmitted more quickly.

dE94 - A technical committee of the CIE (TC 1-29) published an equation in 1995 called CIE94. The equation is similar to CMC but the weighting functions are largely based on RIT/DuPont tolerance data derived from automotive paint experiments where sample surfaces are smooth.
It also has ratios, labeled kL (lightness) and Kc (chroma) and the commercial factor (cf) but these tend to be preset in software and are not often exposed for the user.

Deboss - To press an image into paper so it lies below the surface. Also called tool.

Deckle Edge - Edge of paper left ragged as it comes from the papermaking machine instead of being cleanly cut. Also called feather edge.

Delta-E - It is a single number that represents the difference between two colors. A Delta-E of less than one should be indistinguishable to the human eye.

Delta-Lab and Delta-LCH - One type of difference calculation that some people use is delta-L, delta-a, delta-b (dLab). By breaking the error into its components you can sometimes get a feel for what might be causing the error. If the tolerance region for dE76 is described as a round sphere, then dLab is a square cube. My favorite variation on this idea is delta-LCH. Remember that LCH is Lightness (the same one as in Lab), Chroma (the distance out from the neutral axis - saturation) and Hue (the angle/direction in the 360 degree range). If d-Lab is a box-shaped region then d-LCH is a wedge - like cutting a piece of a flat round ring or washer. The interesting thing about d-LCH is what it can tell you about inkjet behavior. Different LCH values can refer to different problems, for instance:


• larger dL may be a paper difference
,

• larger dC may be paper coating difference
,

• larger dH may be an ink difference.

FOGRA - A German-based Research Institute for the graphic arts. They are very actively involved in maintaining several ISO standards (ISO TC 130) concerning color management and printing. Based on ISO standards, they developed a system of certifications for print providers. proofing systems and proof providers known as FOGRAcert.   - www.fogra.org

Galley Proof - Proof of type from any source, whether metal type or photo type. Also called checker and slip proof.

Laid Finish - Finish on bond or text paper on which grids of parallel lines simulate the surface of handmade paper. Laid lines are close together and run against the grain; chain lines are farther apart and run with the grain.

Laminate - A thin transparent plastic sheet (coating) applied to usually a thick stock (covers, postcards, etc.) providing protection against liquid and heavy use, and usually accents existing color, providing a glossy (or lens) effect.

Landscape - Artist style in which width is greater than height. (Portrait is opposite.)

Lap Register - Register where ink colors overlap slightly, as compared to butt register.

Laser-Imprintable Ink - Ink that will not fade or blister as the paper on which it is printed is used in a laser printer.

Laser Bond - Bond paper made especially smooth and dry to run well through laser printers.

Laser Paper - Very smooth, low-moisture papers manufactured in cut sizes for laser printers and office duplicating equipment. Low moisture prevents paper curling from high heat in laser printers. If your job is designed to run through a laser printer, you should specify laser-compatible offset inks.

Lay Edge - The edge of a sheet of paper feeding into a press.

Lay Flat Bind - Method of perfect binding that allows a publication to lie fully open. Also known as lay flat perfect binding.

Layout - A sample of the original providing (showing) position of printed work (direction, instructions) needed and desired.

Leading - Amount of space between lines of type.

Leaf - One sheet of paper in a publication. Each side of a leaf is one page.

Ledger Paper - Strong, smooth bond paper used for keeping business records. Also called record paper.

Legend - Directions about a specific matter (illustrations) and how to use. In regard to maps and tables, an explanation of signs (symbols) used.

Letter Fold - Two folds creating three panels that allow a sheet of letterhead to fit a business envelope. Also called barrel fold and wrap around fold.

Letter Paper - In North America, 8 1/2” x 11” sheets. In Europe, A4 sheets.

Letterpress - Method of printing from raised surfaces, either metal type or plates whose surfaces have been etched away from image areas. Also called block printing.

Lightweight Paper - Book paper with basis weight less than 40 lbs (60 gsm).

Lignin - Substance in trees that holds cellulose fibers together. Free sheet has most lignin removed; groundwood paper contains lignin.

Line Copy - Any high-contrast image, including type, as compared to continuous-tone copy. Also called line art and line work.

Line Negative - Negative made from line copy.

Linen Finish - Embossed finish on text paper that simulates the pattern of linen cloth.

Lithography - Method of printing using plates whose image areas attract ink and whose nonimage areas repel ink. Nonimage areas may be coated with water to repel the oily ink or may have a surface, such as silicon, that repels ink.

Live Area - Area on a mechanical within which images will print. Also called safe area.

Logo (Logotype) - A company, partnership or corporate creation (design) that denotes a unique entity. A possible combination of letters and art work to create a “sole” entity symbol of that specific unit.

Loose Proof - Proof of a halftone or color separation that is not assembled with other elements from a page, as compared to composite proof. Also called first proof, random proof, scatter proof and show-color proof.

Looseleaf - Binding method allowing insertion and removal of pages in a publication (e.g., trim-4-drill-3).

Loupe - Lens built into a small stand. Used to inspect copy, film, proofs, plates and printing. Also called glass and linen tester.

Low Key Photo - Photo whose most important details appear in the shadows.

Midtones - In a photograph or illustration, tones created by dots between 30 percent and 70 percent of coverage, as compared to highlights and shadows.

MIL - 1/1000 INCHThe thickness of plastic films as printing substrates are expressed in mils.

Misting - Phenomenon of droplets of ink being thrown off the roller train. Also called flying ink.

Mock Up - A reproduction of the original printed matter and possibly containing instructions or direction.

Modem - Mostly used over phone lines, a device that converts electronic stored information from point a to point b. The word is a contraction of modulate/demodulate.

Moire - Undesirable pattern resulting when halftones and screen tints are made with improperly aligned screens, or when a pattern in a photo, such as a plaid, interfaces with a halftone dot pattern.

Moisture - Paper is made to contain between 4% and 7% moisture. Paper will either pick up or lose moisture to reach equilibrium with the relative humidity in which it is used. If the moisture content in a sheet is too high or too low, the paper can curl or build up static, which affects the way it runs through a press, printer or copier.

Monarch - Paper size (7” x 10”) and envelope shape often used for personal stationery.

Mottle - Spotty, uneven ink absorption. Also called sinkage. A mottled image may be called mealy.

Mull - A specific type of glue used for books binding and personal pads needing strength.

Multicolor Printing - Printing in more than one ink color (but not four-color process). Also called polychrome printing.

Natural Color - Very light brown color of paper. May also be called antique, cream, ivory, off-white or mellow white.

• Make sure all images are used at 100%, 300 dpi and are using CMYK color space (unless your printer has noted otherwise).

• Be sure it includes crop marks if necessary.

• If images or colors bleed, be sure to include at least ⅛”-¼” bleed on all sides.

• Make sure to run spell check and have at least one other person proofread your work.

• Include all printer notes about dielines, folds, sizes and finishes.

• Make sure your file is collected and packaged (including fonts) if using a program such as Adobe® InDesign® or QuarkXPress®.

• Include any special notes (e.g., delivery address, collating, etc.).

• If using special colors (e.g., Pantone), be sure to call out color numbers or provide color swatches.

As the eye's sensitivity to hue, chroma, and then lightness differ, the tolerance region around each color that contains acceptable color matches is best represented by an rugby ball-shaped ellipsoid. The more modern color difference formulae use this ellipsoid shape and allow you, the user, to vary several different parameters to tune the numbers to match visual comparisons.

Densitometer - Used to measure the relative degree of darkness within selected materials by measuring light reflected from a surface, such as a printed sheet.

Density - (1) Regarding ink, the relative thickness of a layer of printed ink.

                (2) Regarding color, the relative ability of a color to absorb light reflected from it or block light passing through it.

                (3) Regarding paper, the relative tightness or looseness of fibers.

Density Range - Difference between the darkest and lightest areas of copy. Also called contrast ratio, copy range and tonal range.

Desktop Publishing - Technique of using a personal computer to design images and pages, and assemble type and graphics, then using a laser printer or imagesetter to output the assembled pages onto paper, film or printing plate. Abbreviated DTP.

Device Independent Colors - Hues identified by wavelength or by their place in systems such as developed by CIE. “Device independent” means a color can be described and specified without regard to whether it is reproduced using ink, projected light, photographic chemistry or any other method.

Die - Device for cutting, scoring, stamping, embossing and debossing.

Die Cut - To cut irregular shapes in paper or paperboard using a die.

Diffusion Transfer - Chemical process of reproducing line copy and making halftone positives ready for paste-up.

Digital Dot - Dot created by a computer and printed out by a laser printer or imagesetter. Digital dots are uniform in size, as compared to halftone dots that vary in size.

Digital Imaging Surface™ - Mohawk’s trademarked unique surface treatment for both uncoated and coated papers, specifically engineered to enhance paper-toner performance and yield increased print fidelity.

Digital Papers - Papers designed for the specific demands and imaging techniques of digital presses. This includes dry toner, liquid toner and ink jet presses. They are available in popular digital sheet sizes and rolls. 

Digital Proofing - Page proofs produced through electronic memory transferred onto paper via laser or inkjet.

Direct Digital Color Proof - Color proof made by a laser, ink jet printer or other computer-controlled device without needing to make separation films first. Abbreviated DDCP.

Dog Ear - A letter fold at the side of one of the creases; an indentation occurs.

Dot Gain - Phenomenon of halftone dots printing larger on paper than they are on films or plates, reducing detail and lowering contrast. Also called dot growth, dot spread and press gain.

Dot Size - Relative size of halftone dots as compared to dots of the screen ruling being used. There is no unit of measurement to express dot size. Dots are too large, too small or correct only in comparison to what the viewer finds attractive.

Dots-Per-Inch (DPI) - Measure of resolution of input devices such as scanners, display devices such as monitors.

Double Black Duotone - Duotone printed from two halftones, one shot for highlights and the other shot for midtones and shadows.

Double Bump - To print a single image twice so it has two layers of ink.

Double Burn - To expose film or a plate twice to different negatives and thus create a composite image.

Double Density - A method of recording electronically (disk, CD) using a modified frequency to allow more data storage.

Double Dot Halftone - Halftone double burned onto one plate from two halftones, one shot for shadows, the second shot for midtones and highlights.

Doubling - Printing defect appearing as blurring or shadowing of the image. Doubling may be caused by problems with paper, cylinder alignment, blanket pressures or dirty cylinders.

Double-Thick Cover - Stiff, durable cover papers produced by laminating together two pieces of equal weight paper. The resulting sheet is heavy and strong with excellent printing and folding characteristics.

DPI - Considered as “dots per square inch,” a measure of output resolution in relationship to printers, imagesetters and monitors.

Drawdown - Sample of inks specified for a job applied to the substrate specified for a job. Also called pulldown.

Drill - In the printing arena, to drill a hole in printed matter.

Dropout - Halftone dots or fine lines eliminated from highlights by overexposure during camera work.

Dropout Halftone - Halftone in which contrast has been increased by eliminating dots from highlights.

Dry Back - Phenomenon of printed ink colors becoming less dense as the ink dries.

Dry Offset - Using metal plates in the printing process, which are etched to .15 mm (.0006”) creating a right reading plate, printed on the offset blanket transferring to paper without the use of water.

Dry Trap - To print over dry ink, as compared to wet trap.

Dual-Purpose Bond Paper - Bond paper suitable for printing by either lithography (offset) or xerography (photocopy). Abbreviated DP bond paper.

Dull Finish - Flat (not glossy) finish on coated paper; slightly smoother than matte but considered matte for color management purposes. Also called suede finish, velour finish and velvet finish.

Dummy - Simulation of the final product. Also called mockup.

Duotone - Black-and-white photograph reproduced using two halftone negatives, each shot to emphasize different tonal values in the original.

Duplex Paper - Thick paper made by pasting together two thinner sheets, usually of different colors. Also called double-faced paper and two-tone paper.

Duplexing - The ability of a press or printer to print on both sides of a page without having to manually turn the sheet over.

Duplicator - Offset press made for quick printing.

Dylux - Brand name for photographic paper used to make blueline proofs. Often used as alternate term for blueline.

Electronic Front End (Electronic Composition) - General term referring to a prepress system based on computers.

Electronic Image Assembly - Assembly of a composite image from portions of other images and/or other page elements using a computer.

Electronic Mechanical - Mechanical exclusively in electronic files.

Electronic Publishing - (1) Publishing by printing with device, such as a photocopy machine or ink jet printer, driven by a computer that can change the image instantly from one copy to the next.

                                        (2) Publishing via output on fax, computer bulletin board or other electronic medium, as compared to output on paper.

Emboss - To press an image into paper so it lies above the surface. Also called cameo and tool.

Emulsion - Casting of light-sensitive chemicals on papers, films, printing plates and stencils.

Emulsion Down/Emulsion Up - Film whose emulsion side faces down (away from the viewer) or up (toward the viewer) when ready to make a plate or stencil. Abbreviated ED, EU. Also called E up/down and face down/face up.

Encapsulated Postscript File - Computer file containing both images and PostScript commands. Abbreviated EPS file.

End Sheet - Sheet that attaches the inside pages of a case-bound book to its cover. Also called pastedown or end papers.

English Finish - Smooth finish on uncoated book paper; smoother than eggshell, rougher than smooth.

Engraving - Printing method using a plate, also called a die, with an image cut into its surface.

EP - Abbreviation for envelope.

EPS - Encapsulated Post Script, a known file format usually used to transfer post script information from one program to another.

Equivalent Paper - Paper that is not the brand specified, but looks, prints and may cost the same. Also called comparable stock.

Estimate - Price that states what a job will probably cost. Also called bid, quotation and tender.

Estimator - The individual performing or creating the estimate.

Etch - To use chemicals to carve an image into metal, glass or film.

Face - Edge of a bound publication opposite the spine. Also called foredge. Also, an abbreviation for typeface referring to a family of a general style.

Fake Duotone - Halftone in one ink color printed over screen tint of a second ink color. Also called dummy duotone, dougraph, duplex halftone, false duotone, flat tint halftone and halftone with screen.

Fast Color Inks - Inks with colors that retain their density and resist fading as the product is used and washed.

Feeding Unit - Component of a printing press that moves paper into the register unit.

Felt Finish - Soft woven pattern in text paper.

Felt Side - Side of the paper that was not in contact with the Fourdrinier wire during papermaking, as compared to wire side.

Fifth Color - Ink color used in addition to the four needed by four-color process. Common colors are White, Neon Yellow, and Clear.

Film Gauge - Thickness of film. The most common gauge for graphic arts film is 0.004” (0.1 mm).

Film Laminate - Thin sheet of plastic bonded to a printed product for protection or increased gloss.

Fine Papers - Papers made specifically for writing or commercial printing, as compared to coarse papers and industrial papers. Also called cultural papers and graphic papers.

Fine Screen - Screen with ruling of 150 lines per inch (80 lines per centimeter) or more.

Finish - (1) Surface characteristics of paper.
              (2) General term for trimming, folding, binding and all other post press operations. There are many different finishes that can be added to the final print job, and again is classified as print finishing, being a final procedure.

Finished Size - Size of product after production is completed, as compared to flat size. Also called trimmed size.

Fit - Refers to ability of film to be registered during stripping and assembly. Good fit means that all images register to other film for the same job.

Fixed Costs - Costs that remain the same regardless of how many pieces are printed. Copyrighting, photography and design are fixed costs.

Flat Color - (1) Any color created by printing only one ink, as compared to a color created by printing four-color process. Also called block color and spot color.
                     (2) Color that seems weak or lifeless.

Flat Plan (Flats) - Diagram of the flats for a publication showing imposition and indicating colors.

Flat Size - Size of product after printing and trimming, but before folding, as compared to finished size.

Flexography - Method of printing on a web press using rubber or plastic plates with raised images. Also called aniline printing because flexographic inks originally used aniline dyes. Abbreviated flexo.

Flod - To print a sheet completely with an ink or varnish. Flooding with ink is also called painting the sheet.

Flush Cover - Cover trimmed to the same size as inside pages, as compared to overhang cover. Also called cut flush.

Flyleaf - Leaf, at the front and back of a casebound book that is the one side of the end paper not glued to the case.

Fogging Back - Used in making type more legible by lowering density of an image, while allowing the image to show through.

Foil Emboss - To foil stamp and emboss an image. Also called heat stamp.

Foil Stamp - Method of printing that releases foil from its backing when stamped with the heated die. Also called block print, hot foil stamp and stamp.

Folder - A bindery machine dedicated to folding printed materials.

Fold Marks - With printed matter, markings indicating where a fold is to occur, usually located at the top edges.

Foldout - Gatefold sheet bound into a publication, often used for a map or chart. Also called gatefold and pullout.

Folio (Page Number) - The actual page number in a publication.

For Position Only - Refers to inexpensive copies of photos or art used on mechanical to indicate placement and scaling, but not intended for reproduction. Abbreviated FPO.

Form - Each side of a signature. Also spelled forme.

Form Bond - Lightweight bond, easy to perforate, made for business forms. Also called register bond.

Form Rollers(s) - Roller(s) that come in contact with the printing plate, bringing it ink or water.

Format - Size, style, shape, layout or organization of a layout or printed product.

Formation - Refers to the uniformity and distribution of fibers within a sheet of paper. In a well-formed sheet, solid ink coverage will lay down smoothly. A poorly formed sheet will exhibit a mottled appearance when printed. Formation can be checked by holding the paper up to a light source: a well formed sheet appears uniform, while in a poorly formed sheet the fibers appear as clumps, giving it a cloudy look.

Forwarding - In the case book arena, the binding process which involves folding, rounding, backing, headbanding and reinforcing.

Fountain - Trough or container, on a printing press, that holds fluids such as ink, varnish or water. Also called duct.

Fountain Solution - Mixture of water and chemicals that dampens a printing plate to prevent ink from adhering to the nonimage area. Also called dampener solution.

Four-Color Process Printing - Technique of printing that uses black, magenta, cyan and yellow to simulate full-color images. Also called color process printing, full color printing and process printing.

Free Sheet - Paper made from cooked wood fibers mixed with chemicals and washed free of impurities, as compared to groundwood paper. Also called woodfree paper.

French Fold - A printed sheet, printed one side only, folded with two right angle folds to form a four-page uncut section.

Full-Range Halftone - Halftone ranging from 0 percent coverage in its highlights to 100 percent coverage in its shadows.

Full-Scale Black - Black separation made to have dots throughout the entire tonal range of the image, as compared to half-scale black and skeleton black. Also called full-range black.

Gang - (1) To halftone or separate more than one image in only one exposure.
             (2) To reproduce two or more different printed products simultaneously on one sheet of paper during one press run. Also called combination run.

Gate Fold - A sheet that folds where both sides fold toward the gutter in overlapping layers.

Gathered - Signatures assembled next to each other in the proper sequence for binding, as compared to nested. Also called stacked.

Genuine Felt Finish - A finish applied to paper by means of marking felts while the paper web is still very wet. These felts impart their distinctive textures by gently rearranging the paper fibers. This creates a soft, resilient, texture surface suitable for printing and relief operations.

Ghost Halftone - Normal halftone whose density has been reduced to produce a very faint image.

Ghosting - (1) Phenomenon of a faint image appearing on a printed sheet where it was not intended to appear. Chemical ghosting refers to the transfer of the faint image from the front of one sheet to the back of another sheet. Mechanical ghosting refers to the faint image appearing as a repeat of an image on the same side of the sheet.
                  (2) Phenomenon of printed image appearing too light because of ink starvation.

Gilding - Mostly in the book arena, gold leafing the edges of a book.

Gloss - Consider the light reflecting on various objects in the printing industry (e.g., paper, ink, laminates, UV coating, varnish).

Gloss Ink - Ink used and printed on coated stock (mostly litho and letterpress) so the ink will dry without penetration.

Grade - General term used to distinguish between or among printing papers, but whose specific meaning depends on context. Grade can refer to the category, class, rating, finish or brand of paper.

Graduated Screen Tint - Screen tint that changes densities gradually and smoothly, not in distinct steps. Also called degrade, gradient, ramped screen and vignette.

Grain Direction - Predominant direction in which fibers in paper become aligned during manufacturing. Also called machine direction.

Grain Long Paper - Paper whose fibers run parallel to the long dimension of the sheet. Also called long grain paper and narrow web paper.

Grain Short Paper - Paper whose fibers run parallel to the short dimension of the sheet. Also called short grain paper and wide web paper.

Grain Direction - As the paper web is carried forward on the machine, the majority of fibers orient themselves in the machine direction. When the web of paper is sheeted, the sheets will be grain long (fibers that follow the long side of the sheet) or grain short (they follow the short side). Grain direction should be considered during the design process for best results during printing, folding and converting.

Grammage - Basis weight of paper in grams per square meter (gsm).

Graphic Arts - The crafts, industries and professions related to designing and printing on paper and other substrates.

Graphic Arts Film - Film whose emulsion yields high contrast images suitable for reproduction by a printing press, as compared to continuous-tone film. Also called litho film and repro film.

Graphic Design - Arrangement of type and visual elements along with specifications for paper, ink colors and printing processes that, when combined, convey a visual message.

Graphics - Visual elements that supplement type to make printed messages more clear or interesting.

Gravure - Method of printing using metal cylinders etched with millions of tiny wells that hold ink.

Gray Balance - Printed cyan, magenta and yellow halftone dots that accurately reproduce a neutral gray image.

Gray Component Replacement - Technique of replacing gray tones in the yellow, cyan and magenta films, made while color separating, with black ink. Abbreviated GCR. Also called achromatic color removal.

Gray Levels - Number of distinct gray tones that can be reproduced by a computer.

Gray Scale - Strip of gray values ranging from white to black. Used by process camera and scanner operators to calibrate exposure times for film and plates. Also called step wedge.

Grind Edge - Alternate term for binding edge when referring to perfect bound products.

Grindoff - Approximately ⅛” (3 mm) along the spine that is ground off gathered signatures before perfect binding.

Gripper Edge - Edge of a sheet held by grippers on a sheetfed press, thus going first through the press. Also called feeding edge and leading edge.

Groundwood Paper - Newsprint and other inexpensive paper made from pulp created when wood chips are ground mechanically rather than refined chemically.

GSM - The unit of measurement for paper weight (grams per square meter).

Gutter - In the book arena, the inside margins toward the back or the binding edges.

Hairline (Rule) - Subjective term referring to very small space, thin line or close register. The meaning depends on who is using the term and in what circumstances.

Half-Scale Black - Black separation made to have dots only in the shadows and midtones, as compared to full-scale black and skeleton black.

Halftone - (1) To photograph or scan a continuous tone image to convert the image into halftone dots.
                  (2) A photograph or continuous-tone illustration that has been halftoned and appears on film, paper, printing plate or the final printed product.

Halftone Screen - Piece of film or glass containing a grid of lines that breaks light into dots. Also called contact screen and screen.

Halo Effect - Faint shadow sometimes surrounding halftone dots printed. Also called halation. The halo itself is also called a fringe.

Hard Dots - Halftone dots with no halos or soft edges, as compared to soft dots.

Hard Mechanical - Mechanical consisting of paper and/or acetate and made using paste-up techniques, as compared to electronic mechanical.

Head(er) - At the top of a page, the margin.

Head-To-Tail - Imposition with heads (tops) of pages facing tails (bottoms) of other pages.

Heat-Set Web - Web press equipped with an oven to dry ink, thus able to print coated paper.

Hickey - Spot or imperfection in printing, most visible in areas of heavy ink coverage, caused by dirt on the plate or blanket. Also called bulls eye and fish eye.

High-Fidelity Color - Color reproduced using six, eight or twelve separations, as compared to four-color process.

High-Key Photo - Photo whose most important details appear in the highlights.

Highlights - Lightest portions of a photograph or halftone, as compared to midtones and shadows.

Hinged Cover - Perfect bound cover scored ⅛” (3 mm) from the spine so it folds at the hinge instead of, along the edge of the spine.

HLS - Abbreviation for hue, lightness, saturation, one of the color-control options often found in software, for design and page assembly. Also called HVS.

Hot Spot - Printing defect caused when a piece of dirt or an air bubble caused incomplete draw-down during contact platemaking, leaving an area of weak ink coverage or visible dot gain.

House Sheet - Paper kept in stock by a printer and suitable for a variety of printing jobs. Also called floor sheet.

Hue -  According to the American Heritage Dictionary, hue refers to a particular gradation of color such as a shade or tint, like “all the hues of the rainbow.” An individual frequency in the color spectrum. Humans are capable of discerning over 10 MILLION colors.

I-Tone™ - Mohawk’s proprietary Digital with i-Tone surface has a unique affinity for both liquid and dry toners, offering breakthrough performance on HP Indigo presses and color digital production presses using dry toner. Mohawk’s i-Tone papers have exceptional transfer, adhesion and image durability on smooth and textured papers.

ICC - The International Color Consortium or ICC is the official arbiter of color standards as they relate to the technological implementation of color conversions, quantifications and descriptions for the output devices and software used in the graphic arts industry. The ICC was established in 1993 by a group of industry vendors for the purpose of creating, promoting and encouraging the standardization and evolution of an open, vendor-neutral, cross-platform color management system architecture and components. The outcome of this cooperative effort was the ICC profile specification. ICC profiles are used to describe the color capabilities of input and output devices such as monitors, scanners or printers.  ICC profiles provide a cross-platform device profile format that ensures consistent, device-independent color throughout the entire production process. Device profiles can be used to translate color data created on one device into another device’s native color space. This addresses the issue mentioned above, where toner or ink colors can vary from device to device. The acceptance of this format by operating system and graphic application vendors allows end users to transparently move profiles and images with embedded profiles among different 

operating systems and applications.

Image Area - The actual area on the printed matter that is not restricted to ink coverage.

Imagesetter - Laser output device using photosensitive paper or film.

Imposition - Arrangement of pages on mechanicals or flats so they will appear in proper sequence after press sheets are folded and bound.

Impression - (1) Referring to an ink color, one impression equals one press sheet passing once through a printing unit.

                      (2) Referring to speed of a press, one impression equals one press sheet passing once through the press.

Impression Cylinder - Cylinder, on a press, that pushes paper against the plate or blanket, thus forming the image. Also called impression roller.

Imprint - To print new copy on a previously printed sheet, such as imprinting an employee’s name on business cards. Also called surprint.

Ink Balance - Relationship of the densities and dot gains of process inks to each other and to a standard density of neutral gray.

Ink Fountain - Reservoir, on a printing press, that holds ink.

Ink Holdout - Characteristic of paper that prevents it from absorbing ink, thus allowing ink to dry on the surface of the paper. Also called holdout.

Ink Jet Printing - Method of printing by spraying droplets of ink through computer-controlled nozzles. Also called jet printing.

Inxwell® - A revolutionary and exclusive technology, created and patented by Mohawk, that produces text and cover papers with an uncoated feel, but with the added advantages of superior ink holdout, lower dot gain and significantly increased opacity.

Inner Form - Form (side of the press sheet) whose images all appear inside the folded signature, as compared to outer form.

In-Plant Printer - Department of an agency, business or association that does printing for a parent organization. Also called captive printer and in-house printer.

Inserts - Within a publication, an additional item positioned into the publication loose (not bound in).

Intaglio Printing - Printing method whose image carriers are surfaces with two levels, having inked areas lower than noninked areas. Gravure and engraving are the most common forms of intaglio. Also called recess printing.

Integral Proof - Color proof of separations shown on one piece of proofing paper, as compared to an overlay proof. Also called composition proof, laminate proof, plastic proof and single-sheet proof.

Interleaves - Printed pages loosely inserted in a publication.

ISBN - A number assigned to a published work and usually found either on the title page or the back of the title page. Considered an International Standard Book Number.

Job Lot Paper - Paper that didn’t meet specifications when produced, has been discontinued, or for other reasons is no longer considered first quality.

Job Number - A number assigned to a specific printing project in a printing company for use in tracking and historical record keeping.

Job Ticket - Form used by service bureaus, separators and printers to specify production schedule of a job and the materials it needs. Also called docket, production order and work order.

Jogger - A vibration machine with a slopping platform to even-up stacks of printed materials.

K - Abbreviation for black in four-color process printing. Comes from the "Key" plate. Hence the “K” in CMYK.

Key - (1) The screw that controls ink flow from the ink fountain of a printing press.

          (2) To relate loose pieces of copy to their positions on a layout or mechanical using a system of numbers or letters.

          (3) Alternate term for the color black, as in “key plate.”

Key Negative or Plate - Negative or plate that prints the most detail, thus whose image guides the register of images from other plates. Also called key printer.

Keylines - Lines on a mechanical or negative showing the exact size, shape and location of photographs or other graphic elements. Also called holding lines.

Kiss Die Cut - To die cut the top layer, but not the backing layer, of self-adhesive paper. Also called face cut.

Kiss Impression - Lightest possible impression that will transfer ink to a substrate.

Kraft Paper - Strong paper used for wrapping and to make grocery bags and large envelopes.

M-Weight - Weight of 1,000 sheets of paper in any specific size.

Machine Felt Finish - Rubber marking rolls apply a felt-type finish to paper right before the dryer section. This technique yields a softer surface than embossing and better bulk. The surface is slightly harder than with a genuine felt finish. Though less natural in feel, a machine-felt texture is more economical and provides greater ink holdout because of its compact surface.

Machine Glazed (MG) - Paper holding a high-gloss finish only on one side.MAGENTAOne of the four process colors.

Makeready - (1) All activities required to prepare a press or other machine to function for a specific printing or bindery job, as compared to production run. Also called setup.
                       (2) Paper used in the makeready process at any stage in production. Makeready paper is part of waste or spoilage.

Making Order - Order for paper that a mill makes to the customer’s specifications, as compared to a mill order or stock order.

Male Die - Die that applies pressure during embossing or debossing. Also called force card.

Manuscript (MS) - An author’s original form of work (hand written, typed or on disk) submitted for publication.

Margin - Imprinted space around the edge of the printed material.

Mark-up - Instructions written usually on a “dummy.”

Mask - To prevent light from reaching part of an image, therefore isolating the remaining part. Also called knock out.

Master - Paper or plastic plate used on a duplicating press.

Match Print - A form of a four-color-process proofing system.

Matte Finish - Flat (not glossy) finish on photographic paper or coated printing paper.

Mechanical - Camera-ready assembly of type, graphic and other copy complete with instructions to the printer. A hard mechanical consists of paper and/or acetate, is made using paste-up techniques, and may also be called an artboard, board or paste-up. A soft mechanical, also called an electronic mechanical, exists as a file of type and other images assembled using a computer.

Mechanical Bind - To bind using a comb, coil, ring binder, post or any other technique not requiring gluing, sewing or stitching.

Mechanical Separation - Color breaks made on the mechanical using a separate overlay for each color to be printed.

Mechanical Tint - Lines or patterns formed with dots creating artwork for reproduction.

Metallic Ink - Ink containing powdered metal or pigments that simulate metal.

Metallic Paper - Paper coated with a thin film of plastic or pigment whose color and gloss simulate metal.

Metamerism - In colorimetry, metamerism is the matching of the apparent color of objects without matching their spectral power distribution. Colors that match this way are called metamers. A spectral power distribution describes the proportion of total light given off (emitted, transmitted, or reflected) by a color sample at each visible wavelength; it defines the complete information about the light coming from the sample. However, the human eye contains only three color receptors (three types of cone cells), which means that all colors are reduced to three sensory quantities, called the tristimulus values. Metamerism occurs because each type of cone responds to the cumulative energy from a broad range of wavelengths, so that different combinations of light across all wavelengths can produce an equivalent receptor response and the same tristimulus values or color sensation.

Nested - Signatures assembled inside one another in the proper sequence for binding, as compared to gathered. Also called inset.

Neutral Gray - Gray with no hue or cast.

News Print - Paper used in printing newspapers. Considered low quality and “a short life use.”

Newton Ring - Flaw in a photograph or halftone that looks like a drop of oil or water.

Nipping - In the book binding process, a stage where air is expelled from its contents at the sewing stage.

Non-Integrated Mill - A paper mill that does not have an on-site pulp mill and must purchase all the pulp it requires.

Nonheatset Web - Web press without a drying oven, thus not able to print on coated paper. Also called cold-set web and open web.

Nonimpact Printing - Printing using lasers, ions, inkjets or heat to transfer images to paper.

Nonreproducing Blue - Light blue that does not record on graphic arts film, therefore may be used to preprint layout grids and write instructions on mechanicals. Also called blue pencil, drop-out blue, fade-out blue and nonrepro blue.

Novelty Printing - Printing on products such as coasters, pencils, balloons, golf balls and ashtrays, known as advertising specialties or premiums.

Offset Paper - Uncoated paper designed for use in offset lithography. Important properties include good internal bonding, high surface strength, dimensional stability, lack of curl and freedom from foreign surface material.

Offset Printing - Printing technique that transfers ink from a plate to a blanket to paper instead of directly from plate to paper.

Onion Skin - A specific lightweight type (kind) of paper usually used in the past for air mail. Seldom used today (from the typewriter era).

Opacity - (1) Characteristic of paper or other substrate that prevents printing on one side from showing through the other side.
                 (2) Characteristic of ink that prevents the substrate from showing through.

Opaque - (1) Not transparent.
                 (2) To cover flaws in negative with tape or opaquing paint. Also called block out and spot.

Open Prepress Interface - Hardware and software that link desktop publishing systems with color electronic prepress systems.

Outer Form - Form (side of a press sheet) containing images for the first and last pages of the folded signature (its outside pages) as compared to inner form.

Outline Halftone - Halftone in which background has been removed or replaced to isolate or silhouette the main image. Also called knockout halftone and silhouette halftone.

Over Run - Additional printed matter beyond order. Overage policy varies in the printing industry. Advance questions avoid blind knowledge.

Overlay - Layer of material taped to a mechanical, photo or proof. Acetate overlays are used to separate colors by having some type or art on them instead of on the mounting board. Tissue overlays are used to carry instructions about the underlying copy and to protect the base art.

Overlay Proof - Color proof consisting of polyester sheets laid on top of each other with their image in register, as compared to integral proof. Each sheet represents the image to be printed in one color. Also called celluloid proof and layered proof.

Overprint - To print one image over a previously printed image, such as printing type over a screen tint. Also called surprint.

Page - One side of a leaf in a publication.

Page Count - Total number of pages that a publication has. Also called extent.

Page Proof - Proof of type and graphics as they will look on the finished page complete with elements such as headings, rules and folios.

Pages Per Inch (PPI) - The number of pages in a one inch stack of paper.

Pagination - In the book arena, the numbering of pages.

Painted Sheet - Sheet printed with ink edge to edge, as compared to spot color. The painted sheet refers to the final product, not the press sheet, and means that 100 percent coverage results from bleeds off all four sides.

Panel - One page of a brochure, such as one panel of a rack brochure. One panel is on one side of the paper. A letter-folded sheet has six panels, not three.

Pantone Color  - It is a custom or spot color as defined by the Pantone Measurement System.

Paper And Envelope Converter - A company that constructs various envelopes and other end-use products from parent-size rolls or sheets of paper.

Paper Finishes - There are quite a few finishes on paper and boards. An uncoated paper or board has no finish, and has a matte finish similar to photocopier, or cartridge or an offset paper. It is fibrous under a loupe. Common finishes or coatings can be a silk finish, satin finish or a gloss finish. On a coated paper or board the coating will add to the weight therefore it may feel thinner than an uncoated paper, but will actually weigh the same as an uncoated paper or board. Put simply, uncoated papers often feel thicker than coated papers.

Paper Grade - A system used to classify papers by their common features or content, such as recycled, coated or newsprint papers.

Paper Manufacturer - A company that makes web, sheet and/or cut size paper and sells it through paper merchants and paper stores.

Paper Merchant - A liaison between the paper manufacturer and the paper buyer who offers a number of lines of papers and can offer advice to buyers on the best sheets to specify for particular jobs. Merchants sell paper and envelopes to printers.

Paper Plate - A printing plate made of strong and durable paper in the short run offset arena (cost effective with short runs).

Paper Weights - GSM stands for grams per square meter, meaning how many grams the paper or board will weigh per square meter. For instance the paper that is commonly used in your printer is normally 80 gsm, which is quite thin. The weight will usually increase in implements of 10 grams, 90 gsm, 100 gsm and so on. Most headed paper is normally printed onto 100 gsm, or 120 gsm. Paper weights go up as far as 170 gsm. Over 170 gsm, and it is classed as board weights, which usually go up to 400 gsm. Most business cards and folders usually print onto 350 gsm.

Paper Stores - A retail outlet often run by a paper distributor, which sells paper in cut sizes to end users. Paper stores typically offer a larger assortment of premium printing papers and envelopes than office superstores, which tend to emphasize papers for xerography.

Parallel Fold - Method of folding. Two parallel folds to a sheet will produce 6 panels.

Parent Sheet - Any sheet larger than 11” x 17” or A3.

Paste-Up - To paste copy to mounting boards and, if necessary, to overlays so it is assembled into a camera-ready mechanical. The mechanical produced is often called a paste-up.

Pasteboard - Chipboard with another paper pasted to it.

PCF - Process chlorine free (PCF) refers to papers that contain postconsumer recycled fiber that was processed without the use of any additional chlorine or chlorine compounds. If these papers also contain a percentage of virgin fiber, the virgin fiber must have been processed without the use of any chlorine or chlorine compounds. Because PCF paper contains recycled-content fibers, PCF paper production can also reduce water, energy and virgin fiber usage.

PE - Proofreader mark meaning printer error and showing a mistake by a typesetter, prepress service or printer as compared to an error by the customer.

Perf Marks - On a “dummy” marking where the perforation is to occur.

Perfect Bind - To bind sheets that have been ground at the spine and are held to the cover by glue. Also called adhesive bind, cut-back bind, glue bind, paper bind, patent bind, perfecting bind, soft bind and soft cover. See also Burst Perfect Bind.

Perfecting Press - Press capable of printing both sides of the paper during a single pass. Also called duplex press and perfector.

Perforating - Taking place on a press or a binder machine, creating a line of small dotted wholes for the purpose of tearing-off a part of a printed matter (usually straight lines, vertical or horizontal).

Photoengraving - Engraving done using photochemistry.

Photomechanical Transfer - Brand name for a diffusion transfer process used to make positive paper prints of line copy and halftones. Often used as alternate term for photostat. Abbreviated PMT.

Photostat - Brand name for a diffusion transfer process used to make positive paper prints of line copy and halftones. Often used as alternate term for PMT.

Pica - A unit of measure in the printing industry. A pica is approximately 0.166”. There are 12 points to a pica.

Picking - Phenomenon of ink pulling bits of coating or fiber away from the surface of paper as it travels through the press, thus leaving unprinted spots in the image area.

Pickup Art - Artwork, used in a previous job, to be incorporated in a current job.

Pin Register - Technique of registering separations, flats and printing plates by using small holes, all of equal diameter, at the edges of both flats and plates.

Pinholing - Small holes (unwanted) in printed areas because of a variety of reasons.

Pixel - Short for picture element, a dot made by a computer, scanner or other digital device. Also called pel. 

Planographic Printing - Method whose image carriers are level surfaces with inked areas separated from non-inked areas by chemical means. Planographic printing includes lithography, offset lithography and spirit duplicating.

Plate-Ready Film - Stripped negatives or positives fully prepared for platemaking.

Platemaker - (1) In quick printing, a process camera that makes plates automatically from mechanicals.

                       (2) In commercial lithography, a machine with a vacuum frame used to expose plates through film.

Plates - We have to make a plate for lithographic printing. This is a aluminum sheet that attaches to the printing press with the image that is to be printed, which is etched onto it during the platemaking process. You need 4 of these to make up full color printing, also known as CMYK (cyan, magenta, yellow and key [black]).

Pleasing Color - Color that the customer considers satisfactory even though it may not precisely match original samples, scenes or objects.

PMS - Obsolete reference to Pantone Matching System®. The correct trade name of the colors in the Pantone Matching System® is Pantone colors, not PMS Colors.

PMT - Abbreviation for photomechanical transfer.

Point - (1) Regarding paper, a unit of thickness equating 1/1000”.

             (2) Regarding type, a unit of measure equaling 1/12 pica and .013875” (.351 mm).

Porosity - Often interchanged with air permeability, porosity is a characteristic of a paper’s internal structure. Porosity is the ratio of pore volume to total volume of a sheet. Although rarely measured for premium papers, porosity can indicate how ink will penetrate the sheet.

Portrait - An art design in which the height is greater than the width. Opposite of landscape.

Position Stat - Photocopy or PMT of a photo or illustration made to size and affixed to a mechanical.

Positive Film - Film that prevents light from passing through images, as compared to negative film that allows light to pass through. Also called knockout film.

Post Bind - To bind using a screw and post inserted through a hole in a pile of loose sheets.

Postconsumer Waste Fiber (PCW) - Fiber recovered for papermaking from postconsumer waste paper, which has served its intended use and has been discarded for disposal after passing through the hands of a final user.

Prepress - Camera work, color separations, stripping, platemaking and other prepress functions performed by the printer, separator or a service bureau prior to printing. Also called preparation.

Prepress Proof - Any color proof made using ink jet, toner, dyes or overlays, as compared to a press proof printed using ink. Also called dry proof and off-press proof.

Prepress - To print portions of sheets that will be used for later imprinting.

Press Check - Event at which makeready sheets from the press are examined before authorizing full production to begin.

Press Proof - Proof made on press using the plates, ink and paper specified for the job. Also called strike off and trial proof.

Press Time - (1) Amount of time that one printing job spends on press, including time required for makeready.

                      (2) Time of day at which a printing job goes on press.

Price Break - Quantity at which unit cost of paper or printing drops.

Print Drivers - The instructions that bridge the document creation software and the print hardware, allowing desktop user to print to the device by interpreting the page. Essentially a mini-RIP.

Printer Pairs - Usually in the book arena, consecutive pages as they appear on a flat or signature.

Printer Spreads - Mechanicals made so they are imposed for printing, as compared to reader spreads.

Printing - Any process that transfers to paper or another substrate an image from an original such as a film negative or positive, electronic memory, stencil, die or plate.

Printing Plate - Surface carrying an image to be printed. Quick printing uses paper or plastic plates; letterpress, engraving and commercial lithography use metal plates; flexography uses rubber or soft plastic plates. Gravure printing uses a cylinder. The screen printing is also called a plate.

Print Unit - Assembly of fountain, rollers and cylinders that will print one ink color. Also called color station, deck, ink station, station and tower.

Process Camera - Camera used to photograph mechanicals and other camera-ready copy. Also called copy, camera and graphic arts camera. A small, simple process camera may be called a stat camera.

Process Color (Inks) - The colors used for four-color process printing: yellow, magenta, cyan and black.

Production Checklist - Checklist for prepping files for print production:

For example:

Production Run - Press run intended to manufacture products as specified, as compared to makeready.

Profile Connection Space  - PCS is either CIELAB (L*a*b*) or CIEXYZ.

Proof - When using a digital press, the proof is often a sheet from the press being used, since digital economics allow affordable production of one or two press sheets as a proof. This allows testing to ensure the operator measures twice and cuts once, before pulling the trigger on a large job. Additionally, for many digitally printed jobs, a soft proof (off the monitor) may be adequate and a hard copy proof (off the press/printer) may never be needed.

Proofreader Marks - Standard symbols and abbreviations used to mark up manuscripts and proofs. Also called correction marks.

Proportion Scale - Round device used to calculate percent that an original image must be reduced or enlarged to yield a specific reproduction size. Also called percentage wheel, proportion dial, proportion wheel, whiz wheel and scaling wheel.

Publishing Paper - Paper made in weights, colors and surfaces suited to books, magazines, catalogs and free-standing inserts.

Quality - Subjective term relating to expectations by the customer, printer and other professionals associated with a printing job and whether the job meets those expectations.

Quarto - (1) Sheet folded twice, making pages one-fourth the size of the original sheet. A quarto makes an 8-page signature.

                (2) Book made from quarto sheets, traditionally measuring about 9” x 12”.

Quick Printing - Printing using small sheetfed presses, called duplicators, using cut sizes of bond and offset paper.

Quotation - Price offered by a printer to produce a specific job. Also called a quote.

Rag Paper - Stationery or other forms of stock having a strong percentage content of “cotton rags.”

Rainbow Fountain - Technique of putting ink colors next to each other in the same ink fountain and oscillating the ink rollers to make the colors merge where they touch, producing a rainbow effect.

Raster Image Processor (RIP) - The processor that translates between document creation applications (Photoshop, InDesign, Illustrator, Quark Xpress, Word, etc.) and the printer to generate a printed image. This application contains multiple settings that finely control the expression of the page layout data as desired. A mediocre file can be tweaked into brilliance with proper control of the RIP.

Reader Spread - Mechanicals made in two-page spreads as readers would see the pages, as compared to printer spread.

Ream - 500 sheets of paper.

Recycled Paper - New paper made entirely or in part from old paper.

Reflective Copy - Products, such as fabrics, illustrations and photographic prints, viewed by light reflected from them, as compared to transparent copy. Also called reflex copy.

Register - To place printing properly with regard to the edges of paper and other printing on the same sheet. Such printing is said to be in register.

Register Marks - Cross-hair lines on mechanicals and film that help keep flats, plates, and printing in register. Also called crossmarks and position marks.

Relief Printing - Printing method whose image carriers are surfaces with two levels having inked areas higher than non-inked areas. Relief printing includes block printing, flexography and letter press.

Repeatability - Ability of a device, such as an imagesetter, to produce film or plates that yield images in register.

Reprographics - General term for xerography, diazo and other methods of copying used by designers, engineers, architects or for general office use.

Resolution - Sharpness of an image on film, paper, computer screen, disc, tape or other medium.

Resolution Target - An image, such as the GATF Star Target, that permits evaluation of resolution on film, proofs or plates.

Reverse - Type, graphic or illustration reproduced by printing ink around its outline, thus allowing the underlying color or paper to show through and form the image. The image “reverses out” of the ink color. Also called knockout and liftout.

RGB  - RGB is an additive color model that uses red, green and blue. 

Right Reading - Copy that reads correctly in the language in which it is written. Also describes a photo whose orientation looks like the original scene, as compared to a flopped image.

RIP - Raster Image Processor, the processor that translates between document creation applications (Photoshop, InDesign, Illustrator, Quark Xpress, Word, etc.) and the printer to generate a printed image. This application contains multiple settings that finely control the expression of the page layout data as desired. A mediocre file can be tweaked into brilliance with proper control of the RIP.

Rotary Press - Printing press which passes the substrate between two rotating cylinders when making an impression.

Round Back Bind - To casebind with a rounded (convex) spine, as compared to flat back bind.

Ruby Window - Mask on a mechanical, made with rubylith, that creates a window on film shot from the mechanical.

Rule - Line used as a graphic element to separate or organize copy.

Ruleup - Map or drawing given by a printer to a stripper showing how a printing job must be imposed using a specific press and sheet size. Also called press layout, printer’s layout and ruleout.

Run On - The quantity of printed copies above the original amount required.

Saddle Stitch - To bind by stapling sheets together where they fold at the spine, as compared to side stitch. Also called pamphlet stitch, saddle wire and stitch bind.

Satin Finish - Alternate term for dull finish on coated paper.

Saturation: This term refers to the vividness of hue or purity of a color. Intensity can be increased or decreased to suit. A general rule of thumb is to ensure that there is at least 1% tonal value of one of the four color channels.

Scale - To identify the percent by which photographs or art should be enlarged or reduced to achieve, the correct size for printing.

Scanner - Electronic device used to scan an image.

Score - To compress paper along a straight line so it folds more easily and accurately. Also called crease.

Screen Angles - Angles at which screens intersect with the horizontal line of the press sheet. The common screen angles for separations are black 45 degree, magenta 75 degree, yellow 90 degree and cyan 105 degree.

Screen Density - Refers to the percentage of ink coverage that a screen tint allows to print. Also called screen percentage.

Screen Printing - Method of printing by using a squeegee to force ink through an assembly of mesh fabric and a stencil.

Screen Ruling - Number of rows or lines of dots per inch or centimeter in a screen for making a screen tint or halftone. Also called line count, ruling, screen frequency, screen size and screen value.

Screen Tint - Color created by dots instead of solid ink coverage. Also called Benday, fill pattern, screen tone, shading, tint and tone.

Selective Binding - Placing signatures or inserts in magazines or catalogs according to demographic or geographic guidelines.

Self Cover - Usually in the book arena, a publication not having a cover stock. A publication only using text stock throughout.

Self Mailer - A printed item independent of an envelope. A printed item capable of travel in the mailing arena independently.

Separated Art - Art with elements that print in the base color on one surface and elements that print in other colors on other surfaces. Also called pre-separated art.

Separations - Usually in the four-color process arena, separate film holding images of one specific color per piece of film. Black, Cyan, Magenta and Yellow. Can also separate specific PMS colors through film.

Serigraphic Printing - Printing method whose image carriers are woven fabric, plastic or metal that allow ink to pass through some portions and block ink from passing through other portions. Serigraphic printing includes screen and mimeograph.

Service Bureau - Business using imagesetters to make high resolution printouts of files prepared on microcomputers. Also called output house and prep service.

Setoff - Undesirable transfer of wet ink from the top of one sheet to the underside of another as they lie in the delivery stack of a press. Also called offset.

Shade - Hue made darker by the addition of black, as compared to tint.

Shadows - Darkest areas of a photograph or illustration, as compared to midtones and highlights.

Sheetfed Press - Press that prints sheets of paper, as compared to a web press.

Sheetwise - Technique of printing one side of a sheet with one set of plates, then the other side of the sheet with a set of different plates. Also called work and back.

Sheffield - The method used to measure the smoothness of paper. The lower the number, the smoother the paper.

Shingling - Allowance, made during paste-up or stripping, to compensate for creep. Creep is the problem; shingling is the solution. Also called stair stepping and progressive margins.

Side Stitch - To bind by stapling through sheets along, one edge, as compared to saddle stitch. Also called cleat stitch and side wire.

Signature - Printed sheet folded at least once, possibly many times, to become part of a book, magazine or other publication.

Size - Compound mixed with paper or fabric to make it stiffer and less able to absorb moisture.

Slip Sheets - Separate sheets (stock) independent from the original run positioned between the “printed run” for a variety of reasons.

SMOOTHNESS - The surface quality of a sheet of paper, related to the flatness of the sheet. Smoothness affects ink and toner receptivity. The Sheffield scale measures smoothness. A higher value typically indicates a rougher sheet. For example, Navajo’s smoothness is 45, whereas vellum offset may have a rating of 300+.

SOFT DOTSHalftones dots with halos.

Solid - Any area of the sheet receiving 100 percent ink coverage, as compared to a screen tint.

Soy-Based Inks - Inks using vegetable oils instead of petroleum products as pigment vehicles, thus are easier on the environment.

Specialty Printer - Printer whose equipment, supplies, workflow and marketing is targeted to a particular category of products.

Specifications - Complete and precise written description of features of a printing job such as type size and leading, paper grade and quantity, printing or binding method. Abbreviated specs.

Spectrophotometer - Instrument used to measure the index of refraction of color.

Specular Highlight - Highlight area with no printable dots, thus no detail, as compared to a diffuse highlight. Also called catchlight and dropout highlight.

Spine - Back or binding edge of a publication.

Spiral Bind - To bind using a spiral of continuous wire or plastic looped through holes. Also called coil bind.

Split Fountain - Technique of putting ink colors next to each other in the same ink fountain and printing them off the same plate. Split fountains keep edges of colors distinct, as compared to rainbow fountains that blend edges.

Split Run - (1) Different images, such as advertisements, printed in different editions of a publication.

                    (2) Printing of a book that has some copies bound one way and other copies bound another way.

Spoilage - Paper that, due to mistakes or accidents, must be thrown away instead of delivered printed to the customer, as compared to waste.

Spot Color or Varnish - One ink or varnish applied to portions of a sheet, as compared to flood or painted sheet.

Spread - (1) Two pages that face each other and are designed as one visual or production unit.

                (2) Technique of slightly enlarging the size of an image to accomplish a hairline trap with another image. Also called fatty.

Standard Viewing Conditions - Background of 60 percent neutral gray and light that measures 5000 degrees Kelvin the color of daylight on a bright day. Also called lighting standards.

Stat - Short for photostat, therefore a general term for an inexpensive photographic print of line copy or halftone.

Statistical Process Control - Method used by printers to ensure quality and delivery times specified by customers. Abbreviated SPC.

Step And Repeat - Prepress technique of exposing an image in a precise, multiple pattern to create a flat or plate. Images are said to be stepped across the film or plate.

Stock Order - Order for paper that a mill or merchant sends to a printer from inventory at a warehouse, as compared to a mill order.

Stocking Paper - Popular sizes, weights and colors of papers available for prompt delivery from a merchant’s warehouse.

Strength - Paper strength is determined more by the nature of its fiber than its thickness. High bursting strength is achieved by forming paper with a tight weave of long fibers so that they are both vertical and horizontal within the paper.

String Score - Score created by pressing a string against paper, as compared to scoring using a metal edge.

Strip - To assemble images on film for platemaking. Stripping involves correcting flaws in film, assembling pieces of film into flats and ensuring that film and flats register correctly. Also called film assembly and image assembly.

Stumping (Blocking) - In the book arena, hot die, foil or other means in creating an image on a case bound book.

Substance Weight - Alternate term for basis weight, usually referring to bond papers. Also called sub weight.

Substrate - Any surface or material on which printing is done.

Subtractive Color - A subtractive color model begins with white or the reflection of all colors. Colorants are then added, shift the reflective values and produce the desired color. This model is used in mixing paints, dyes, inks and natural colorants to create a range of colors. Light passes through the toner, bounces off the substrate (paper) and reflects back, with the red, green and blue colors being subtracted by the toner before the light reaches the eye of the viewer.

Subtractive Primary Color - Yellow, magenta and cyan. In the graphic arts, these are known as process colors because, along with black, they are the inks colors used in color-process printing.

Supercalendared Paper - Paper calendered using alternating chrome and fiber rollers to produce a smooth, thin sheet. Abbreviated SC paper.

Surprint - Taking an already printed matter and re-printing again on the same.

Swatch Book - A book in a variety of forms, indicating specific stock in specific colors in a specific thickness.

SWOP - Abbreviation for specifications for web offset publications, specifications recommended for web printing of publications.

Tabloid- Using a broadsheet as a measure, one half of a broadsheet.

Tag - Grade of dense, strong paper used for products such as badges and file folders.

Tagged Image File Format - Computer file format used to store images from scanners and video devices. Abbreviated TIFF.

Target Ink Densities - Densities of the four process inks as recommended for various printing processes and grades of paper. See also Total Area Coverage.

Template - Concerning a printing project’s basic details in regard to its dimensions. A standardized layout.

Text Paper - Designation for printing papers with textured surfaces such as laid or linen. Some mills also use ‘text’ to refer to any paper they consider top-of-the-line, whether or not its surface has a texture.

Thermography - Method of printing using colorless resin powder that takes on the color of underlying ink. Also called raised printing.

Thumbnails - Initial ideas jotted on virtually anything in regard to initial concept of a future project.

Tint - Screening or adding white to a solid color for results of lightening that specific color.

Tip In - Usually in the book arena, adding an additional page(s) beyond the normal process (separate insertion).

Tone Compression - Reduction in the tonal range from original scene to printed reproduction.

Total Area Coverage - Total of the dot percentages of the process colors in the final film. Abbreviated for TAC. Also called density of tone, maximum density, shadow saturation, total dot density and total ink coverage.

Touch Plate - Plate that accents or prints a color that four-color process printing cannot reproduce well enough or at all. Also called kiss plate.

Trade Shop - Service bureau, printer or bindery working primarily for other graphic arts professionals, not for the general public.

Transparency - Positive photographic image on film allowing light to pass through. Also called chrome, color transparency and tranny. Often abbreviated TX.

Trap - To print one ink over another or to print a coating, such as varnish, over an ink. The first liquid traps the second liquid. See also Dry Traps and Wet Traps.

Trim Marks - Marks on each corner of the sheet indicating where the sheet will be guillotined to the finished size. Also called crop marks or cut marks.

Trim Size - The size of the printed material in its finished stage (e.g., the finished trim size is 5 1/2” x 8 1/2”).

Uncoated Paper - Paper that has not been coated with clay. Also called offset paper.

Undercolor Addition - Technique of making color separations that increases the amount of cyan, magenta or yellow ink in shadow areas. Abbreviated UCA.

Undercolor Removal - Technique of making color separations such that the amount of cyan, magenta and yellow ink is reduced in midtone and shadow areas while the amount of black is increased. Abbreviated UCR.

Universal Copyright Convention (UCC) - A system to protect unique work from reproducing without knowledge from the originator. To qualify, one must register their work and publish a © indicating registration.

Unsharp Masking - Technique of adjusting dot size to make a halftone or separation appear sharper (in better focus) than the original photo or the first proof. Also called edge enhancement and peaking.

Up - Term to indicate multiple copies of one image printed in one impression on a single sheet. “Two up” or “three up” means printing the identical piece twice or three times on each sheet.

UV Coating - Liquid applied to a printed sheet, then bonded and cured with ultraviolet light.

Value - The shade (darkness) or tint (lightness) of a color. Also called brightness, lightness, shade and tone.

Varnish - Liquid applied as a coating for protection and appearance.VELLUM FINISHSomewhat rough, toothy finish.

Velox - Brand name for high-contrast photographic paper.

Viewing Booth - Small area or room that is set up for proper viewing of transparencies, color separations or press sheets. Also called color booth. See also Standard Viewing Conditions.

Vignette - Decorative design or illustration fade to white.

Vignette Halftone - Halftone whose background gradually and smoothly fades away. Also called degrade.

Virgin Paper - Paper made exclusively of pulp from trees or cotton, as compared to recycled paper.

VOC - Abbreviation for volatile organic compounds, petroleum substances used as the vehicles for many printing inks.

Wash Up - To clean ink and fountain solutions from rollers, fountains, screens, and other press components.

Waste - Unusable paper or paper damage during normal makeready, printing or binding operations, as compared to spoilage.

Watermark - Translucent logo in paper created during manufacturing by slight embossing from a dandy roll while paper is still approximately 90 percent water.

Web Break - Split of the paper as it travels through a web press, causing operators to rethread the press.

Web Gain - Unacceptable stretching of paper as it passes through the press.

Web Press - Press that prints from rolls of paper, usually cutting it into sheets after printing. Also called reel-fed press. Web presses come in many sizes, the most common being mini, half, three-quarter (also called 8-page) and full (also called 16-page).

Wet Trap - To print ink or varnish over wet ink, as compared to dry trap.

Window - (1) In a printed product, a die-cut hole revealing an image on the sheet behind it.

                  (2) On a mechanical, an area that has been marked for placement of a piece of artwork.

Wire Side - Side of the paper that rests against the Fourdrinier wire during paper making, as compared to felt side.

With The Grain - Parallel to the grain direction of the paper being used, as compared to against the grain. See also Grain Direction.

Wood-Free Paper - Made with chemical pulp only. Paper usually classified as calendared or super-calendared.

Working Film - Intermediate film that will be copied to make final film after all corrections are made. Also called buildups.

Writing Paper - Suitable for pen and ink, pencil, laser printing or offset printing. Writing grades are designed for letterheads and corporate identity programs.

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