Legacy CRDs

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

If a color configuration does not provide an output profile via the Profile key in setreproduction, CIE-based colors is rendered using the current CRD in the PostScript language gstate. A CRD is essentially another way of encoding the PCS to device conversion for one rendering intent in an ICC profile. There is only one CRD in the gstate which makes it impossible to correctly apply rendering intent selections from the job.

It may be desirable for a legacy product to use separate CRDs for each ICC rendering intent. It is possible to do so with a RIP extension to the /Profile key of setreproduction (see Profile in setreproduction):

CODE

<<
  /Profile <<
    /Default <<
      /ProfileType 1
      /Output <<
        /RelativeColorimetric <CRD>
        /Perceptual <CRD>
        /Saturation <CRD>
      >>
    >>
  >>
>> setreproduction

The value of /Profile is a dictionary that supplies up to three CRDs and is used by the RIP in the same manner as the B2Ax tables an ICC profile. The RIP selects which intent to use for each object using the same criteria as ICC intents. This is based on the current rendering intent and rendering intent overrides. For more information see Rendering intent overrides.

When CRDs are used in setreproduction in this manner, the PQR transforms within the CRD are ignored. These are conventionally used to apply chromatic adaptation. Instead, the RIP applies its own chromatic adaptation as described in Chromatic Adaptation Transform (CAT). Also, for relative intents, an additional mapping is performed as explained in RelativeWhitePoint . These are applied by the RIP as though they were derived from equivalent values in an ICC profile; the illuminant, and the media white point within the mediaWhitePointTag, respectively.

Legacy CRD dictionaries may also be used with object-based color management (see Object-based color management). This makes it possible to use a different set of CRDs for different object types or to use CRD dictionaries with some object types and ICC profiles with the others.