[cairo] Spot colors (and CMYK)

Chris Murphy lists at colorremedies.com
Sat Feb 20 21:04:39 PST 2010

On Feb 20, 2010, at 7:50 PM, ecir hana wrote:

> On Sun, Feb 21, 2010 at 3:36 AM, Chris Murphy <lists at colorremedies.com> wrote:
>> Many spot colors have no CMYK equivalent that ensures reversibility back into its original XYZ/LAB value.
> Sorry, I don't understand again. A profile is just a mapping between
> two spaces, be it LUT or some function, right? So why can't I create a
> profile which would say CMYK(a, b, c, d) = LAB(x, y, z)? I know it
> would probably be very different than say SWOP but pure theoretically,
> ICC should allow this, no?

Yes, but then why even bother using CMYK? You'd be specifying CMYK values that have no correlation to any actual CMYK output device. For that matter you could say 100K only = fluorescent orange in LAB. Yes it would work, but this is such a departure from reality I think it's asking for other problems. There's no advantage to specifying alternates in CMYK, when the color is out of gamut for any conventional CMYK space. Just use XYZ, LAB or ICCBased wide gamut RGB to define the alternate.

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

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