CMYK Overprint mode

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

CMYK Overprint mode is useful for color managing opaque jobs prepared for a particular CMYK press, as is common when proofing jobs in the pre-press market. These jobs may contain additional spot colorants. This is achieved by internally rendering into a virtual device with these properties:

the color model is CMYK, the value of the VirtualDeviceSpace, (see Transparency mode ).
the virtual device is tagged with the CMYK intercept profile from setinterceptcolorspace. Here, the virtual device is emulating a real device that:
was characterized with the CMYK intercept profile, and
can render the spots without conversion to the alternate space.

The virtual device internally renders overprints and compositing without including any of the effects of setreproduction or calibration, which are applied in the conversion of all colors from the virtual device to the output device. The result is both colorimetric CMYK overprints, and a simulation of spot overprints.

If the job contains other color spaces, for example; /DeviceRGB, the blend space color management (see Blend space color management ), will be applied the same as for transparency jobs. The quality of the output depends partly on the quality of the ICC profiles used in the configuration, and on the size of the color gamuts in the various profiles. Whether or not this is undesirable can only be determined by testing.

In this mode:

/DeviceCMYK objects are overprinted colorimetrically.
the treatment of spots is identical to the SpotsOnly mode.
all other color spaces will be converted into the CMYK intercept profile of the virtual device, leading to an extra color transform which may not be desirable.

The CMYK Overprint mode of OverprintPreview is activated using the setinterceptcolorspace operator:

CODE

<< /OverprintPreview true >> setinterceptcolorspace