[cairo] Subtractive API, part 0

[Jon Cruz]

On Jan 29, 2010, at 2:30 PM, ecir hana wrote:

>> 
>> ignoring the color meaning of CMYK values is just not useful
> 
> I don't agree. In practise, sometimes it happens that you just know
> nothing about the CMYK values, sometimes it happens that you know all
> about the CMYK values. Sometimes, you get some design manual stating
> just some values for a logotype and all you could possible do is to
> type those values in. Or sometimes you get a picture not tagged with a
> profile and all you can do is to let it print out. On the other hand,
> sometimes, you know precisely well what you are about going to do, you
> know the paper and you want rich black. 40% 30% 30% 100% rich black.

Yes. Which interestingly enough shows a general "not useful" workflow. That is, one can wrangle raw numbers directly, but if things are not precisely controlled in the print shop, you *will* get different prints from one day to the next.

You case of the logotype has two solutions. Either have some spot (aka pantone) color specified, or get something specific on the CMYK, such as SWOP for north america.

For an untagged picture, one would first assume a base RGB, such as sRGB or Adobe RGB. If it is a CMYK picture, then going with the local printshop standard for CMYK would be ok... but explicitly asking and then stating that you'll be making an explicit assumption is much better.

In those cases, you end up with a client at least aware that they will need to review and approve proofs. Sometimes they'll even account for this in their scheduling. Without all this, though, one is just asking for trouble. Hence it is not too useful.