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This paper presents an overview of the architecture of Apple Computer's forthcoming color management system release. ColorSyncTM 2.0 is the first of a new generation of operating system based color management systems. The major goal of this architecture is to provide a scalable, flexible and extensible solution to managing color on the desktop for both the end user and application developer. The ambitious scope of this goal necessitated a level of complexity far beyond the first release of ColorSyncTM. ColorSyncTM 1.0 was introduced at MacWorld in January 1993. It is a "plug-in" framework which permits thirdparties to ship color-matching software which users may employ without the need for a complete proprietary environment. After this introduction, Apple then actively solicited feedback from third party developers for several months. An agreement was reached on the profile format at the FOGRA meeting at the Seybold conference in October 1993. This agreement lays the foundation for version 2.0 of the Extension software. Acceptance of the profile format has since been announced by several platform vendors. The ColorSyncTM 2.0 profile format incorporates significant changes from version 1 .0. The new format is a diskbased tagged-element structure allowing selective access to profile data whereas the ColorSync 1 .0 profile format is a memory resident structure. The 1 .0 default CMM uses algorithmic matching derived from work by Apple ATG. This method is relatively fast and accurate for monitors, but is less than optimal for printers. The new format supports use of multidimensional color lookup table transforms. ColorSyncTM 2.0 requires either a 68020 or later processor or a 601 PowerPC or later processor. In addition, a version of the Macintosh Operating System 7.1 or later is also required (which includes Apple's Component Manager). ColorSyncTM 2.0 relies on the Component Manager for the basis of the framework which allows plug-and-play capability for third party color-modeling implementations. ColorSyncTM 2.0 consists of an Extension file from which the resident dispatcher is installed at system startup and a separate Control Panel to provide the user control of the ColorSyncTM System Profile. The ColorSyncTM 2.0 architecture is divided into five parts; 1) the resident dispatcher, 2) profile management, 3) color conversion methods, 4) color modeling methods (CMMs), and 5) the ColorSyncTM profile format. The following sections describe each of these five parts individually. The profile manager, color conversion methods and color modeling methods are all implemented using the Apple Component Manager. Components are used to dynamically load and run executable object code on demand. In addition, the component manager provides database facilities to track each component in the system, allowing the resident dispatcher to call the appropriate component without forcing unreasonable memory requirements on each application. This paper places an emphasis on the profile format since this format provides crossplatform capabilities for color management systems.
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