This class represents a separation color space.
A separation color space represents a single custom color. Most
typically these are spot colors used in printing.
For example the conventional color space for printing is CMYK
and for that you can use the DeviceCMYK color space.
However you might wish to add support for a custom ink like gold
or silver which will print correctly when passed to a printer which
supports this ink.
The separation color space includes a conversion function so
that it will also provide a good representation on screen and on
normal CMYK printers.
This is definitively detailed in:.
The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Section:
184.108.40.206, page 157.