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RE: [CSS3 gcpm] CMYK colors and allowed values.

From: David Perrell <davidp@hpaa.com>
Date: Fri, 31 Jul 2009 11:42:11 -0700
To: "W3C style mailing list" <www-style@w3.org>
| RGB is not a perceptual color spec.

Ambiance can be controlled by an author and a monitor can be calibrated. It
is at least possible for sRGB to be unambiguous, yes?

Clearly, RGB can't sub for CMYK. Converting 100%K, 30%C text to RGB and back
again can really muck things up. But why would anyone use CSS to mark up
documents for which appearance is critical?

I don't see inclusion of CMYK without profiles as disastrous. Spec'ing CMYK
colors on paste-ups didn't require printer profiles. But images are another
story, and I don't see CSS markup targeting a specific type of print device.
If included, CMYK should always be a *secondary* color spec, to be used *if*
the device supports it.

I fail to see the logic of a color spec in a module titled 'Generated

| All desktop inkjet printers are RGB for example.

I believe there are drivers (e.g. Adobe PressReady, ghostscript pcl3) that
can print CMYK with standard halftone screens on CMYK HP PCL printers (e.g.
970C, 1220C).

| 2. A page description language absolutely should not make it easy to
| create ambiguous content.

I tend to agree, but CSS has always been a pretty loose PDL, and I've run
into some folks absolutely anal about keeping it that way. I can't imagine
CSS being used to mark up 6-color top-quality print jobs with 300dpi CMYK

David Perrell
Received on Friday, 31 July 2009 18:43:32 UTC

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