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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