[cairo] Spot colors (and CMYK)

[Bill Spitzak]

Jon Cruz wrote:

> Actually the pantone CMYK "alternatives" are quite an ugly mess, and not nearly sRGB based.
> 
> Instead they were based on physical efforts to create close results... *however* they are not common CMYK.
> 
> Instead they are very custom. In order to get closer to their ink values, Pantone had set up those samples to print inks in custom orders with custom screening that is not compatible with the norms used by print houses running CMYK.

I believe this corresponds to what I suspect.

A better way of saying it is: Pantone sets the CMYK alternatives so that 
the simplistic conversion to sRGB produces "correct" results on the 
screen. Therefore those colors have nothing to do with CMYK inks on any 
printer.

This means we will lose nothing by doing the simple conversion to sRGB 
and putting that in the API.