[cairo] Spot colors (and CMYK)

Chris Murphy lists at colorremedies.com
Wed Feb 17 11:46:14 PST 2010

On Feb 17, 2010, at 12:39 PM, Bill Spitzak wrote:

> Kai-Uwe Behrmann wrote:
>> Such direct from device to device converting technices are not 
>> standardised in ICC.
> This is EXACTLY why I don't want Cairo to do this.
> Do you really think if Cairo defined how it understands color profiles 
> it would support this? Apparently not.
> Exactly how do you think your magical color correction is going to not 
> be instantly obsolete if you force the back end to do this work?

I don't think anyone is suggesting that either DeviceLinks, or their implied functions, be implemented in Cairo. These are workflow specific issues, that need to be optionally dealt with at proofing and printing stages.

But if you disallow CMYK, or K only, then people cannot express an intent to print K only text on a device that will produce lawsuit worthy output if it's not printed as K only. Text needs to be specifiable as /devicegray or /devicecmyk as well as the fact it is text.

In all normal cases for display or printing to a local inkjet printer or laser printer, if you've preserved the correct metadata, the PDF will contain the necessary information to correctly print the artwork, as intended, even if there are 4D to 3D to 4D conversions occurring. And you don't need to be responsible for actually making those conversions - the printing backends should do this at print time, because only they have the awareness of how the printer behaves anyway.

Chris Murphy
Color Remedies (TM)
New York, NY
Co-author "Real World Color Management, 2nd Ed"

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