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Managing Color With ColorSync


What Should a ColorSync-Supportive Application Do?

Your ColorSync-supportive application can provide a rich set of color-matching features. Your application can color match images, pixel maps, bitmaps, and even individual colors. In addition to color matching, you can handle such tasks as color conversion, color gamut checking, soft proofing of images, profile management, profile searching and accessing, reading individual tagged elements within a profile, embedding profiles and profile identifiers in documents, extracting embedded profiles and profile identifiers, and modifying profiles and profile identifiers.

Your application can provide an interface that offers pop-up menus or other user interface items allowing a user to choose which profile to associate with an image and how an image is rendered. It can show the user the colors of an image that are in or out of gamut for a particular device on which the image is to be produced and how ColorSync adjusts for colors that are out of gamut. This allows the user to preview differences that occur in the color-matching transition between gamuts and make corrections if necessary.

Most of the terms and operations mentioned in this section are defined in Introduction to Color and Color Management Systems and Introduction to ColorSync ; see also Glossary .

At a Minimum

ColorSync allows your application to preserve high fidelity to the original colors of an image--whether the image was created using your application or another--by supporting the use of e mbedded profiles. Your application can take advantage of a profile embedded along with an image, matching the original colors of the device used to create the image to those of the destination display or printer. Even if your application doesn't support some of the more advanced features that ColorSync affords, such as soft proofing, you should color match images using the source profile, if one is identified and available.

At a minimum, your application should preserve images tagged with a profile by not stripping out picture comments used to embed profiles or by leaving profiles in documents that use other methods to include them.

It is important for your application to tag an image with the profile for the device used to create the image and to preserve existing tagging because a picture that is not tagged assumes use of a default profile as described in Setting Default Profiles . If the picture is moved to a different system that uses a different default profile, the picture will display differently. Providing Minimal ColorSync Support explains how to preserve embedded profiles, and Embedding Profiles and Profile Identifiers explains how to tag an image. Some of these features are described in greater detail in the rest of this material.

Storing and Handling Profiles

Profiles for use with the ColorSync Manager are stored in the ColorSync Profiles folder. The precise location of this folder can vary for different versions of ColorSync, as described in Setting Default Profiles . When you install ColorSync, the ColorSync Profiles folder contains a selection of display profiles for all Apple color monitors, as well as default profiles for standard color spaces and profiles for several Apple printers.

Starting with ColorSync 2.5, a user can select a default profile for certain color spaces from the ColorSync control panel, as described in Setting Default Profiles . Also starting with version 2.5, the Monitors & Sound control panel allows the user to select a separate profile for each monitor, as described in Monitor Calibration and Profiles .

Your application specifies the profiles for color matching when the application calls a ColorSync Manager function. For most functions, the ColorSync Manager uses one of the default profiles if your application doesn't specify a profile. Some functions require that you explicitly specify a profile by reference.

Device drivers for ColorSync-supportive input and output devices, such as scanners and printers, may install the profiles they use in the ColorSync Profiles folder, making them available to your application for color matching or gamut checking. If your application creates device link profiles, as described in Creating and Using Device Link Profiles , you should place those profiles in the ColorSync Profiles folder.

Your application can provide the interface to allow a user to choose a profile for a specific device. Using the ColorSync Manager functions described in Profile Searching , your application can search the ColorSync Profiles folder and display information about available profiles.

See Developing Your ColorSync-Supportive Application for a list of programming examples that demonstrate many of these features. As described in Providing Minimal ColorSync Support , your application should, at a minimum, leave profile information intact in the documents and pictures that it imports or copies into its own documents.


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