The None colorant in DeviceN spaces

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

The PDF specification [PDF1.6] allows the use of the None colorant in /DeviceN spaces, whereas the PostScript language specification [RB3] says an error should be thrown.

The RIP allows the use of None components for both PDF and the PostScript language using rules that are Harlequin extensions as described in Decomposing a DeviceN colorant list. The components corresponding to the None are usually discarded. This can be useful when intercepting device spaces for special effects, for example;

CODE

<<
  /DeviceCMYK [/DeviceN [/None /Magenta /None /None] /DeviceCMYK {}]
>> setinterceptcolorspace

is one way of ignoring the CYK components of /DeviceCMYK. Another example:

CODE

<<
  /DeviceCMYK [/DeviceN [/None /NCD-Spot /None /None] /DeviceCMYK {}]
>> setinterceptcolorspace

also ignores the CYK components. The M component is assigned to NCD-Spot, which is present in an NCD and is subject to named color management using it.