Separation and DeviceN alternate spaces

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

The PostScript language and PDF specifications restricts the alternate space of /Separation and /DeviceN color spaces to standard device and CIE-based spaces. The RIP also allows the use of /Separation or /DeviceN, for example; if a job specifies this color space:

CODE

[ /Separation /JobSpot /DeviceCMYK {0 0 0} ]

If JobSpot is intercepted by an NCD with a /DeviceN ColorSpace, the result after named color management might look like this:

CODE

[ /Separation
  /JobSpot
  [/DeviceN [/RenderedSpotA /RenderedSpotB] /DeviceCMYK {0 0}]
  {dup}
]

which illustrates a case where named color management is emulating JobSpot with a mixture of two colorants, RenderedSpotA and RenderedSpotB. The assumption is that both of these are renderable on the device, but that is not necessary.

Nested /Separation or /DeviceN spaces will not be intercepted by NCDs. In the above example, if RenderedSpotA and RenderedSpotB are not renderable, they are converted by the tint transform, even if they are present in an NCD. In this simple example their color values aer transferred to Cyan and Magenta.