[cairo] Spot colors (and CMYK)

Jon Cruz jon at joncruz.org
Mon Feb 22 20:45:51 PST 2010

On Feb 22, 2010, at 12:55 PM, Bill Spitzak wrote:

> This sounds like you want direct exact control over the ink levels.
> My proposal is to support it with a "here is the name of the current color" api. The back end can use this for any purpose whatsoever. I would think this name would literally be the same text that is put into the pdf. Other back ends can ignore the name and use the sRGB equivalent that is sent at the same time.
> This has nothing to do with "color management" in fact it is the complete opposite. The sRGB equivalent is not required to have ANYTHING to do with the spot color.

You're completely missing the point.

Cairo will do blends and such. 

Cairo will take *something* in.

Cairo will emit PDF out.

Cairo needs to emit proper CMYK+spot details to the PDF.

Cairo *should* at the same time be able to 'preview' to an RGB display.

If that preview does not have ANYTHING to do with the spot color specified, then most even semi-profesionals will laugh their heads off at Open Source and dismiss such software as mere toys.

So Cairo needs to decide to either do PDF correctly, or not do PDF at all. "broken" or "works only for on-screen" PDF keeps our software in the "toy" category.

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