Color management is the process by which you try to match color conditions in a set of devices (e.g., scanner, monitor and printer). These devices produce color using different methods; therefore, they may display the same color value differently, and may not all display the same range of color values (see color gamut, below). In other words, color is device-dependent: the color that you see will change depending on the device that's producing it.
A color management system (CMS) is a collection of color management software tools used to try to make color device-independent. Ideally, the colors on your monitor should accurately represent the colors in a scanned image, and the colors you see on the final output. A CMS maps colors from the color gamut of one device into a device-independent color space, and then maps those colors to the color gamut of another device.
The process of returning a device to known color conditions. Commonly done with devices that change color frequently, such as monitors (phosphors lose brightness over time) and printers (proofers and other digital printing devices can change output when colorant or paper stock is changed).
The process of creating a profile that describes the unique color conditions found on a particular device. For monitors, this includes colorimetric descriptions of its phosphors and the color temperature of its white point. For printers, this includes descriptions of the inks, paper stock, and line ruling. In a CMS, you characterize the calibrated monitor by creating an ICC device profile.
Color Matching Method, also called a Color Engine. The specific software component in a CMS that does the color conversion calculations from one device's color space to another using the ICC device profiles (e.g., ColorSync or Kodak CMS).
The total range of colors reproduced by a device. A color is said to be "out of gamut" when its position in one device's color space cannot be directly translated into another device's color space. For example, the total range of colors that can be reproduced with ink on coated paper is greater than that for uncoated newsprint, so the total gamut for uncoated newsprint is said to be smaller than the gamut for coated stock. The CMYK gamut is generally smaller than their RGB gamut.
The dimensional coordinate system used to numerically describe colors. Some models include: Red, Green, Blue (RGB); Hue, Lightness, Saturation (HLS); Cyan, Magenta, Yellow, Black (CMYK); and Lightness, a, b (Lab).
The specific range of colors in a particular model (e.g., RGB, Lab, CMYK). For example, if you have an RGB master image and convert it to CMYK using an ICC device profile for a CMYK composite printer, then, using the same master RGB document, convert the image to CMYK using a different ICC device profile, each resulting CMYK image will be in a different CMYK color space. Also called Gamut.
A device that measures the luminosity of RGB light. When used with software, it can be used to create ICC device profiles for monitors. Many high-end monitors targeted at the pre-press professional contain such devices internally (e.g., Barco self-calibrating monitor) or have a colorimeter attached (e.g., Radius PressView).
A system-level CMS developed by Apple Computer, Inc. for Mac OS. Adobe PageMaker, Adobe Photoshop, and Adobe Illustrator currently support ColorSync 2.x and later.
A device that measures the density of exposed film (in transmissive mode) or printed inks (in reflective mode). They are used in the printing industry to measure the output accuracy of halftone screens as discreet dot percentages. For that reason, they are used as a calibration tool for imagesetters and printing presses.
The International Color Consortium established in 1993 by eight industry vendors (including Adobe Systems) to create, promote, and encourage the standardization and evolution of an open, vendor-neutral, cross-platform color management system architecture and components.
ICC Device Profile
A file that describes how a particular device (e.g., monitor, scanner, printer, or proofer) reproduces color (i.e., its specific color space). Profiles can be either generic or custom.
Output based from a printing press that uses four colors (cyan, magenta, yellow, and black) to create the illusion of continuous tone images. For that reason, cyan, magenta, yellow, and black are also known as process colors (CMYK).
A printing device a service bureau uses to create images as contracts (also called a contract proof) to match in the final output from the offset press. Traditional proofers create prints from negative separations; digital proofers create ink-jet (e.g., IRIS) or dye-sublimation (e.g., Kodak, 3M) composite prints.
Reference Color Space (RCS)
A reference color space is a device-independent theoretical color model used by a CMM (color engine) for translating colors from one device's gamut to another. The CIE Lab is an example of a Reference Color Space. This component is built into the CMM, it is neither alterable nor visible to users.
The method a CMM uses for converting (i.e., mapping) colors from one device's gamut to another. The three methods are called Perceptual, Saturation, and Relative Colorimetric. In PageMaker and Illustrator the names of the rendering intents are called Image, Graphics, and Colorimetric, but they do the same thing.
A device that measures either 16 or 32 discreet bandwidths of visible light. When used with software, it can be used to create ICC device profiles for monitors and output devices.