Inside Macintosh: What's New in ColorSync 2.5 /

Monitor Calibration and Profiles

Ever since ColorSync was first introduced, a common question from end users has been "Where is the ColorSync profile for my monitor?" The answer is that because some monitor manufacturers do not supply ColorSync profiles for their products, purchasers of third-party monitors may not have access to a profile that is specific to their monitor. As a result, they are unable to use ColorSync effectively.

Even when a user has a factory-supplied profile, switching to a different monitor setup can reduce the profile's accuracy. For example, if the user changes the monitor's gamma value and white point, the original profile is no longer useful. The user needs a calibration application to generate a new ColorSync profile for the new monitor settings.

Starting with version 2.5, ColorSync uses the Monitors & Sound control panel to provide a monitor calibration framework to help users obtain the monitor profiles they need. Monitors & Sound Control Panel for ColorSync 2.5 shows the new Monitors & Sound control panel. Note that the list of gamma values (Mac Standard Gamma, uncorrected gamma) has been removed because that function is now part of the calibration process.

Because Monitors & Sound displays a panel for each available monitor, a user can also select, for each monitor, a separate profile from the list of available profiles. For information on how to set monitor profiles in your code, see Monitor Profile Functions .

The Calibrate button provides the launching point for calibration. A user can calibrate each monitor and create one or more color profiles for each, based on variations in gamma, white point, and so on. AppleVision and Apple ColorSync monitors are self-calibrating, so you will not see a Calibrate button for these monitors, unless there is at least one third-party calibrator installed in your Extensions folder.

Calibrating a monitor can be a challenging task for a naive user, but Apple Computer supplies a default calibrator that leads the user through a series of calibration steps. Using the default calibrator, even a novice should have a reasonable chance for success.

Figure 1. Monitors & Sound Control Panel for ColorSync 2.5

Note

The calibration framework uses a plug-in architecture that is fully accessible to third-party calibration plug-ins. When a user clicks on the Calibrate button, the Monitors & Sound control panel provides a list of all available calibrator plug-ins. To appear in the list, a plug-in must meet the following criteria:

• It must be stored in the Extensions folder.
• It must be a shared library (file type 'shlb' ).
• Its shared library must export the symbols CanCalibrate and Calibrate.
• It should have a unique creator type (registered with Apple).
• The name of the library's code fragment (specified in the 'cfrg' resource) must be unique (among all currently loaded shared libraries) and begin with 'Cali' . For example, you might want to name the library by appending your creator type to 'Cali' .