Color management

Colormanagement is a technology to calibrate the color of input devices (e.g scanners or digital cameras), the monitor and output devices (e.g printers or offset presses). Parts of this technology are implemented in the Operating System, the API or direct in the application. A main concept in color management is the working space. This describes a color space, which is not connected to a special device. The mostly used working space is sRGB. The concept for color management in Windows and Microsoft Office products is, that every driver for an input device makes a color transformation from the colorspace of the device to sRGB. For the output device or the monitor, the driver has to make a color transformation from sRGB to the colorspace of the output device. This kind of implementaion of color management is very user friendly, because there is need for any configuration. But the quality of the results depends totally on the quality of the color transformations, which are part of the drivers. A more open concept of color management is the use of an ICC[?]-compatible color management system. The International Color Consortium[?] (ICC) is a industry consortium, which has defined an open standard for a CMM (Color Matching Module) at OS level, and color profiles (ICC-profiles) for the devices and the working space. Another concept of the ICC is to make color profiles a part of file formats like TIFF, JPEG, EPS[?], PDF, and SVG.

A clear implemantation of colormanagement in the user interface of the OS would be the configuration of the monitor profile and the profile for the working space in the system-configuration and the configuration of the device profiles in the scanner or printer-driver. Analyzing the actual implementation of color management at the level of the OS, the drivers and the applications, shows that there is a big confusion about color management at the side of the software architects for OS Systems and the software developers of drivers and applications. Actual problems are:

• There is offen no clear concept of the software architects of the OS, how to implement color mangement on OS-Level including guidelines for the developers of applications and drivers how to use the color management possibilties of the OS.
  • There is not the concept of a choosable working space and a monitor-profile in the graphics architecture and in the window system of the OS. On MacOS this is possible, but nearly all applications ignore it...
  • The OS architecture for printer drivers doesn´t allow the configuration of profiles for a working space and a device space.
• Some important fileformats like EPS[?] are incompatible for colormangement on the host computer. For colormatching of EPS-Files, a PostScript-RIP is necessary.
• Color mangement for the printer is some times implemented on different levels like into the application, on OS-Driver Level or into the PostScript-RIP. This can cause double or triple colormatching with unwanted results.

More informations about color management for software developers are found here:

• ICC-Specs at http://www.color.org/icc_specs2
• Overview about Windows an color management http://www.microsoft.com/hwdev/tech/color/default.asp
• MacOS X and ColorSync: http://developer.apple.com/technotes/tn/tn2035
• Open Source: http://www.coloraid.de/