Color Management Systems

With today's desktop color, systems must be able deal with color images from multiple sources.

These include Photo CD, digital cameras, different scanners in different locations and computer generated images, all with different characteristics. Output devices are numerous including digital printers and proofers along with image/platesetters and both conventional and digital presses.

Often the output devices are geographically remote from where the images are processed.

The process may involve several transformations between different color spaces (scanner RGB, monitor RGB, CIE color spaces, CMYK for proofing devices and final press CMYK).

Multiple people may be involved at different stages.

It is difficult to assign responsibility for color quality.

Color Management Systems (CMS) have been designed to deal with these issues.

Using characteristics of devices, these systems have been developed to calculate the transformations necessary to keep color consistent throughout the production chain.

These systems are still being developed, but eventually most of the problems will disappear and color consistency will be transparent to the user.

Systems would not be possible without use of device independent color spaces such as CIE (Lab, LCh, XYZ, Yxy, etc.)

The existence of these models allows vendors to specify the color performance of their devices in terms of the CIE color spaces.

So for each device there is a CIE equivalent for any given color.

Device Characterization

Need to define how a device inputs/outputs color in a device independent fashion and create device profiles for sources and destinations.

A device profile characterizes each device used for input or output of color in terms of a CIE-based color space.

Profiles may be generic (class of devices), device specific (particular device) or custom (specific user needs).

A device also needs to be calibrated to maintain optimum reproducible performance.

Color management allows the user to focus on creation and reproduction without having to be concerned about the complex mechanics of device behavior.

It also gives the user a greater degree of control of the reproductive process.