Custom color management modules

This page applies to Harlequin v13.1r0 and later; both Harlequin Core and Harlequin MultiRIP

The Harlequin RIP may be extended using custom written color management modules (interchangeably referred to as Alternate CMMs), each of which may provide one or both of two broad functions that extend color management:

the replacement of the built-in ICC CMM with an alternative, e.g. LittleCMS;
additional color spaces that may be used within setinterceptcolorspace and setreproduction color configuration operators to modify colors in ways that cannot be achieved with ICC profiles.

An introduction to how these features might be used in practice is provided in:

A color pipeline may contain several transforms, as dictated by the color configuration, and that of the setreproduction operator in particular. The setreproduction operator may configure a series of NextDevice transforms, each of which forms a transform within the full color pipeline. For the purposes of an Alternate CMM, a color transform is one of:

one ICC input profile and one ICC output profile.
a single ICC devicelink profile.
a single custom color space.

If an Alternate CMM is active, each transform in the pipeline is potentially implemented by the Alternate CMM. Also, transforms between transparency groups are optionally handled by the Alternate CMM.

The Alternate CMM API describes the programming interface to Alternate CMMs and the details of how a color pipeline and its invocation interact with the Alternate CMM.

The SDK provides a number of Color management examples which are fully working and illustrate some possible uses for Alternate CMMs.