Tips for Great Color

Tips on Producing Great Color

Good color starts by calibrating all of the devices within the color work flow.
Devices should be calibrated often to ensure that they have not “drifted.” The frequency depends upon your reliance on color. As you know from reading this blog, calibrating brings the device to a known, stable state, and is a baseline.

Calibrating your monitor is just as important as calibrating the print device.
Whatever color space you might be working in, unless your monitor presents you with controlled, managed color, what you see will not match what you get. First, it’s important to think about the problem correctly. The goal isn’t to match the prints to the monitor or the converse. The goal is to make sure both the monitor and the prints reflect, as accurately as possible, the information that is actually in the digital file. There are lots of methods for calibrating your monitor, and it can get quite involved.

Here is a video showing how YOU can calibrate your monitor for FREE.

The major manufacturers of monitor calibration packages for the casual user are Datacolor (the Spyder series ), X-Rite (the i1 series, PANTONE Huey and the ColorMunki) and Integrated Color (ColorEyes Display Pro). All these products are of excellent quality. The first two have several price levels of packages with varying capabilities.

The more expensive packages may include features you don’t need, such as printer profiling and projector calibration, and the ability to customize calibration settings beyond the defaults. The accepted standard is to calibrate to a color temperature of 6500K, a gamma of 2.2 (for both PC and Mac platforms) and a luminance of 90 cd/m2 and these will be the default setting in all the packages. But some of the less expensive packages may not do everything you need, such as luminance adjustment. Check the details.

Some laptop screens may not be able to be calibrated properly, and older or very inexpensive computers may not be able to use a profile. Apple laptops will need the ColorEyes software mentioned above.

An issue with Windows is a utility called Adobe Gamma. If it is in your Startup file it will be loaded on startup and override your calibration settings. Simply go to Start > Programs > Startup, right click the Adobe Gamma Loader and click Delete. (If it’s not there, don’t be concerned.) Don’t be nervous about doing this. It only turns it off as a startup item; it does nothing to what is installed your computer.

A custom ICC profile should be created for each device within the Color Supply Chain.
This process ensures accurate and automatic translation of color values from one device to another, minimizing time and waste during the production process. A Device Link Profile can be established to link devices commonly used in the production process, eliminating the need to specify individual device profiles each time.

Paper, inks and toner impact the ultimate color result. Creating individual device profiles for each paper type, ink and/or toner used delivers a more consistent result. For example, if a proof is being generated on a glossy, coated stock, but the final product is being produced on a matte uncoated stock, these custom profiles can produce a more consistent result.

Spot colors can add time and cost to a printed project. Not all spot colors can be faithfully reproduced with CMYK four-color process. Designers and printers should carefully consider the colors that they are using within the context of the project’s budget and desired outcomes. Many tools exist that can help users determine whether or not a special color can be faithfully reproduced using a CMYK match. It is often necessary to use spot colors to consistently match special corporate colors and to ensure absolute color consistency across a distributed printing process.

Make sure you aren't "duplicating" any colors. 

Look through the color palette in your page layout software. Remove any duplicate colors you find, and reassign the corresponding objects and layers accordingly.

Make sure you give your colors the same names in each application you use for the project. 

For example, make sure you give the color the same name in InDesign as you give it in Photoshop and Illustrator. This will help reduce confusion and ensure the colors separate properly when preparing the piece for print.

Communication among all constituents in the color work flow is essential. This communication should include sharing of ICC profiles, discussion about paper and ink types and proofing models, and more. In doing so, good, consistent color can be produced across widely varying geographies and output technology types.

Using a good RIP in the production process is a critical element in the color work flow. It alleviates many color issues and reduces training challenges. Consistency in settings within the RIP is key to delivering repeatable and known color.

When using digital cameras or scanners for input, if you want your colors to be consistent from shot to shot, or scan to scan, include a color target in the first frame/scan of a sequence. When it comes to processing, set the grey point (and black and white points) using the target reference frame, and your software will match the subsequent batch of images.

Always color correct images in the largest RGB color space available. When images are converted from RGB to CMYK, you lose color information—a lot of it. As a result, you (and your color management tools) have fewer colors to work with, or average, when attempting to make color changes to an image. Also, when images are converted from RGB to CMYK, you’re creating the black separation and reducing the amount of CMY in the image at the same time. Depending upon how much CMY is eliminated in the separation, it can be very difficult—or even impossible—to make color adjustments to an image.

When designing for color output, avoid large solids. While lithographic presses have the ability to reproduce solids evenly, toner-based devices have a tendency to mottle, show unevenness, or even banding. This is because ink and toner are radically different materials. When toner is applied to paper, it is dry. Toner is not actually absorbed into the paper fibers, instead, it is fused to the sheet using both heat and fuser oil, creating a bond. Consistency lies in how evenly the toner was applied to the paper, and how evenly it was fused to the paper.

If tints and large solids must be used in a design, there are some ways to help counteract the uneven appearance associated with toner-based devices. First, try applying a filter (Photoshop Add Noise or Texture filters work well) to the large tint or solids. Another option is to also break up large color areas with other design elements such as text, images, or illustrations.

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

Device Link Profiles

Color profiling software also can generate device link profiles.

A device link is a type of International Color Consortium profile that contains two profiles inside of one. In order to create a device link profile, you select the two profiles, along with settings, and then save these ‘linked’ profiles as a device link profile. A device Link profile always contains a source color space and a destination color space, and the conversions always move from the source color space to the destination color space, saving time in file preparation and processing. They are most useful to people who repeatedly use the same specific configuration.

Why might device link profiles be required?

One example is when a scanner application does not embed the source profile in the document containing the image it creates. Storing the scanner’s profile eliminates the need to request the appropriate source profile each time the user wants to print with a configuration involving that scanner.

Perhaps a user also may want to see how a scanned image looks when printed using a specific printer, or may want to look at many images captured on the same scanner at different times before printing the final image.

Since the same devices are involved each time, the graphics application displays a list of device link profiles that the user had previously created for various configurations, allowing the user to select the appropriate device link profile for the current activity.

Another reason to use device link profiles has to do with maintaining channels in color conversions. Typical ICC color conversions require all of the colors in the file being converted — including the black channel. device link color conversions allow the user to maintain the K channel so that the color conversion can happen without any changes to the K channel — such as converting K type to CMYK type. This can be important when making color conversions for certain types of inkjet proofing where you need to maintain the black channel.

It is even more important for making color conversions during plate generation. When used during ripping or plate generation, the black channel must be maintained and device links are a must. In this scenario the device link is used to make the press simulate another printing condition, or to match a printing condition such as GRACoL. Not every platesetter RIP can use device link profiles, but many can, and for those with RIPs that can’t, there are third party applications that can provide these conversions.

Device links are a required component in conversions between different printing conditions, e.g. from offset to gravure. Black channel conversion is achieved with exacting results. Whether single black or rich black output is specified, the device link will manage the requirement.

Currently device link profiles can’t be embedded or assigned in applications like Photoshop because they contain mathematical information for a color conversion rather than describing a color space. Because of this, device link profiles are more complicated and less flexible than traditional ICC profiles and are classified by the ICC as a special type of profile.

A few other points about device links:

• only one rendering intent is available, that which was selected at the time the link was created. 
• links cannot be embedded into images 
• the rendering intent encapsulated in the link is selected in the 'default intent' field in the profile's header. 
• a profile sequence tag in link profiles documents the profiles used to create the profile. 

If you are looking to create your own device link profiles, I personally like the iPublishPro 2 software from XRite.

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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