RE: wide CMYK
RE: wide CMYK
- Subject: RE: wide CMYK
- From: Rick Gordon <email@hidden>
- Date: Thu, 1 Nov 2001 13:16:05 -0800
Setting up a custom CMYK in Photoshop comes pretty close (but not quite lossless).
You could set up ink values with idealized RGB values like:
<C 0,255,255>, <M 255,0,255>, <Y 255,255,0>, <R 255,0,0>, <G 0,255,0>, <B 0,0,255>, <CMY 0,0,0>, <W 255,255,255>, <K 0,0,0>
The values, in some cases won't quite hold, but they'll be in the zone.
I suppose that you might also make a case for a 400% total ink limit in this abstract case.
The gamut is much wider than a normal CMYK, but not quite perfect round-trip. And I see that some blues/cyans shift slightly.
Ultimately, I'm not sure of the value of it, though.
---
Another way to take advantage of the false K separation technique in RGB is to make a duplicate, separate it to CMYK, possibly using values like an extremely light black generation and a very low black ink limit (50% or 60%). then stretch the black back to full tonality with a curve, sharpen the hell out of it, and paste it back into the RGB document as a new layer in multiply mode. Then adjust it with a curve to lighten the dark end and a lowered blending mode opacity. You can definitely bring some extra contrast into the very deep tones this way. Just experiment with the values.
Rick Gordon
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On 10/31/01 at 1:31 PM -0800, Jon Zax wrote in a message entitled
"wide CMYK":
In the latest Electronic Publishing mag, Dan Marguis writes of using the black plate of a CMYK file to fix a problem photo.
It occurred to me that it should be possible to create a CMYK profile that includes the entire gamut of a large RGB space. While this is not normally how a CMYK profile is used, I can see it as another tool to work on images even going back to RGB after with minimal lose of data.
Any ideas about how to create such an artificial CMYK space ?
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RICK GORDON
EMERALD VALLEY GRAPHICS AND CONSULTING
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