(v13) The importance of setpagedevice

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

If OverprintPreview is active, it is important that a setpagedevice is executed after the color configuration is applied, otherwise the color management may be applied incorrectly to the first page of some PostScript language jobs. The color configuration includes the setinterceptcolorspace, setreproduction, setrenderingintent, and setcalibration color operators, and various color related user and system parameters. The reason for the potential bad color in some jobs is subtle.

When compositing transparency groups, the color management used for a group is taken from the graphics state when the group was opened. When OverprintPreview is active, an extra transparency group is created for the page during setpagedevice. Therefore, if the color configuration is changed, a setpagedevice call is required to ensure that the new color configuration is used for the compositing phase.

When processing jobs in PDF or one of the image formats, the RIP executes an internal setpagedevice. So, the extra setpagedevice call is not necessary for these PDLs, but adding it is still a wise precaution.

Color configurations can be changed between pages. The recommended way to do this is within a BeginPage setpagedevice hook procedure (see setpagedevice in [RB3]). One use case for doing this is where odd and even pages are treated differently.