(v13) Rules for background separations

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

• All marks to appear in background separations must be drawn in spot colors used only for that purpose. If this is not done, objects in the main separations may vanish.
• All marks to appear in background separations must be drawn before any other marks on the page. (This implies that they would normally be drawn during executions of the BeginPage procedure in the page device). If this is not done, subsequent objects drawn in the background colors may vanish. Non-background objects drawn later does not cause knockouts in the background separation, even though it is drawn first—it is always printed in full.
• All marks to appear in background separations must be overprinted. This means that when they are encountered in the display list for separations other than the background ones, they do not interfere because of overlap or cause problems marking off the edge of the sheet. If this is not done, the background marks may knockout holes in the other separations—to check for this during rendering puts too much overhead on ordinary jobs—so it is important to use true setoverprint before drawing the embellishments.

Background separations are always positioned at (0,0) on each sheet. Therefore, the coordinate systems for the whole sheet and the background marks are the same.

A background separation is built by choosing an arbitrary name for the spot color for drawing marks on the separation and declaring it with the /Background key to addseparationorder.

There may be several background separations so that marks can appear on some sheets and not others. For example, there might be one background separation for marks that appear on every sheet, and one for each individual sheet.

Since the objects drawn in the background separations are always spot colors, the Separation color space must be used.

In a controlled environment where jobs are known to be EPS files, the background marks can simply precede the job. However, in general, they have to be put in the BeginPage procedure, so that they are repeated at the beginning of each page (taking into account any page imposition as well—see (v13) Imposition).