Named separations to be used in addition to the color channels
specified in the ColorSpace.
Separate color channels for the named separations are only
created if the output type is TIFF and the output color space is
CMYK or RGB.
If these conditions are met, ABCpdf will write each separation
to a different TIFF page and set the TIFF ink name to the name of
This property can be either a comma-separated list of the named
separations, or it can be the keyword 'All', which indicates that
all named separations referenced by the page should be output.
Note that ABCpdf will not create spot colors if it encounters a
page group color space that is different from the specified color
space. However, in this situation, it will still write the process
colors individually to the TIFF output.