[cairo] Spot colors (and CMYK)

[Jon Cruz]

On Jan 21, 2010, at 10:09 AM, Bill Spitzak wrote:

> 
> 
> 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.

Well... not really.

At least not in the newer Pantone information I'd seen. The key was that their "CMYK" values had higher fidelity than the RGB values, and one could not round-trip without loss.

And specifically, the modern Pantone CMYK numbers do not use the simplistic transformation.