NextDevice named colorants in alternate CMMs

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

CMM custom color spaces may use /DeviceN spaces for either input or output, with no restriction on the number of components. A /DeviceN input space can only be used as the InputColorSpace of a /NextDevice transform. One example of this use was given in NextDevice named colorants . Here is another example:

CODE

(customers-color-space) setalternatecmm

<<
  /OverprintPreview /SpotsOnly
>> setinterceptcolorspace

<<
  /Profile (iccprofiles/SWOP.icc) (r) file
  /NextDevice <<
    /InputColorSpace [
      /CMM
      (CMYKGldTq-CMYKOGSv)
      [ DeviceN [/Cyan /Magenta /Yellow /Black /Gold /Turquoise] /DeviceCMYK {pop pop} ]
      [ DeviceN [/Cyan /Magenta /Yellow /Black /Orange /Green /Silver] /DeviceCMYK {pop pop pop} ]
    ]
  >>
>> setreproduction

which uses the (CMYKGldTq-CMYKOGSv) CMM custom color space to convert 6 input components to 7 output components. It must be used with an output device that supports the 7 output colorants.

It is worth repeating that Gold and Turquoise colorants from the job are passed directly to the /NextDevice and bypass other color management. And the RIP will map components to the correct order and fill in missing components with zero values before calling the C function implementing the CMM custom color space.

The configuration uses OverprintPreview because we wish to simulate spot color overprints in this workflow.