Re: this editing space debate on CS user
Re: this editing space debate on CS user
- Subject: Re: this editing space debate on CS user
- From: Chris Murphy <email@hidden>
- Date: Mon, 25 Nov 2002 11:15:14 -0700
On Monday, November 25, 2002, at 10:40 AM, bruce fraser wrote:
I've certainly captured colors that lie in that small squeak of
yellow-orange. It's not unreasonable to suppose I might want to
reproduce them.
I was wrong, it's actually right on the b* axis so it's just plain
yellow, if anything it might have the slightest bit of green associated
with it. In any event, it's so small that I seriously doubt being able
to reproduce it would make any difference. It looks to me like at best
a 3% protrusion. The final arbiter would be to print out a test image
that contained such a yellow color.
Perceptual rendering doesn't do anything to the gamut boundary --
that's a fixed analog limitation.
The profile's perception of where the boundary is, is frequently
expanded with most gamut mapping algorithms. If you open a Granger
rainbow on-screen, and turn on gamut warning, then go to Proof Setup
and change the rendering intent, what is considered in-gamut and
out-of-gamut depends on the rendering intent.
And I wouldn't take US Sheetfed Coated v.2.0, good though it is, as
the canonical definition of what can be acheived on sheetfed press
with coated stock.
Fair enough. I've only tested six press profiles so far. But the
Sheetfed Coated v2 profile is the only one that has even the slightest
protrusion out of the Adobe RGB gamut. While most of us don't like
Matchprints, even the Seybold shootout Matchprint produced by a Creo
Spectrum is totally contained inside Adobe RGB.
I just found an IRIS2-something or other profile I have that's a couple
of years old. Looks like I'm getting about an 6% protrusion of just
yellow, along the b* axis, outside of Adobe RGB.
Kodak Approval - oddly enough 2% protrusion of yellow. That's weird, I
wonder what yellow pigment they're using...
Now when I go to something like an Epson 10000, dye ink, on premium
luster, I end up with a miniscule slice of magenta hardly worth
mentioning, and then a wide but mostly narrow band starting at about
tomato red through yellow, thickest part at yellow, looks like maybe
8-10% protrusion.
Anyway - I think for offset printing, Adobe RGB is plenty sufficient.
Colormatch RGB on the other hand looks like it could be a problem, but
I'd still test it out to confirm this with my own eyes.
It's undoubtedly true that for people whose only concern is press
output, the vast majority will see no practical benefit, on press
output, from an editing space larger than Adobe RGB. It's a big
stretch to go from that to "there's no practical benefit to an editing
space larger than Adobe RGB."
That concluding statement was in a paragraph discussing press spaces,
so the context was in regards to the selection of an editing space with
a printing press being the destination. You don't really think that I
was saying there would be no benefit to anything bigger than Adobe RGB,
even to something like a film recorder.
Chris Murphy
Color Remedies (tm)
Boulder, CO
www.colorremedies.com
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