Adobe InDesign CS3 Bible

Defining Color Terms

Color is an expansive (and sometimes confusing and esoteric) concept in the world of publishing. The following definitions, however, should start you on your way to a clear understanding of the subject.

• Build: Attempts to simulate a color-model color by overprinting the appropriate percentages of the four process colors.

• CIE LAB: A standard that specifies colors by one lightness coordinate and two color coordinates ‚ green-red and blue-yellow. The first part of the name means Comit ƒ International d' ƒ °clairage, an international standards group , and the second part refers to the mathematical approach used to describe the colors in a cubic arrangement: luminance, a -axis, and b -axis.

• CMYK: A standard that specifies colors as combinations of cyan, magenta , yellow, and black. These four colors are known as process colors.

• Color gamut : The range of colors that a device, such as a monitor or a color printer, can produce. Each color model has a different color gamut.

• Color model: An industry standard for specifying a color, such as CMYK or Pantone.

• Color separation: A set of four photographic negatives ‚ one filtered for each process color ‚ shot from a color photograph or image. When overprinted, the four negatives reproduce that original image.

• Color space: A method of representing color in terms of measurable values, such as the amount of red, yellow, and blue in a color image. The color space RGB represents the red, green, and blue colors on video screens.

• Four-color printing: The use of the four process colors in combination to produce most other colors.

• Hexachrome: Pantone's six-color alternative to CMYK. It adds green and orange inks for more accurate color reproduction in those hues, as well as enhanced versions of black, magenta, cyan, and yellow inks. (InDesign does not support Hexachrome unless you use a third-party utility.)

• Process color: Any of the four primary colors in publishing ‚ cyan, magenta, yellow, and black (known collectively as CMYK). A six-color, high-fidelity variant produced by Pantone is called Hexachrome.

• RGB: The standard used by monitors , and the abbreviation from the three colors in it: red, green, and blue. One of the biggest hurdles to producing color documents that look as you'd expect is that computers use RGB while printers use CMYK, and the two don't always produce colors at the same hue.

• Spot color: A single color applied at one or more places on a page, such as for a screen or as part of an illustration. You can use more than one spot color per page. Spot colors can also be process colors.

• Swatchbook: A table of colors collected together as a series of color samples. The printer uses a premixed ink based on the color model identifier you specify; you look up the numbers for various colors in the table of colors in a swatchbook.