Re: RGB vs CMYK: gamut and some important notes for CMYK users

From: Katharine Thayer ^lt;[email protected]>
Date: 12/04/04-06:10:43 PM Z
Message-id: <>

Mr X, who doesn't want me to mention his name, is having an argument
with me that I'm not having with him. How many times have I said that
whatever works is the right way to do it? That if the SWOP profile works
for someone, that's great? That I don't think there's any way to
determine with any acceptable precision whether RGB or default CMYK is
better in some objective sense, so I don't think it's ultimately a very
interesting question; furthermore presenting comparisons really isn't
very useful, since we'll all get different results and it won't come to
anything that could be generalized into a rule.

I've already said, and shown a couple preliminary prints that indicate,
that my comparisons will show RGB looking much better in color balance
than CMYK, but I've also said in some detail that I wouldn't make
anything of that because it doesn't really mean anything in a larger
sense of determining which is *better.* All it will mean is that I am
very good at printing RGB separations. So I don't really see the point,
although I am planning to work at it when I can. It's slow because I
have a heart problem that is limiting my activities. I can sit and type,
as long as I don't do it too long at a stretch, but I have difficulty
these days with things that require standing, walking back and forth,
lifting and so forth, like gum printing. In the last two months there
haven't been more than two or three days that I've been able to go out
to the studio, and I've had other things to do while I was there. This
personal information isn't really any of Mr. X's business, but since he
has made it his business more than once by rather rudely demanding why I
haven't produced the comparison prints, this is why.

How many times have I said there is room for many different points of
view on this, there is not a right answer to the question of how to
produce color separations? If anyone thought I was criticizing his
personal choice of separation methods, this would be a misreading of
what I have said. I've never questioned or criticized Mr X's test
methods; I have no issue with his tests and never have. My only issue
was with the categorical statement that RGB gives distorted color; I
disagreed with that statement; this whole argument has stemmed from that
categorical statement and my disagreement with it. But to say I disagree
with the statement that RGB separations can't give true color is NOT
the same thing as saying that RGB separations are Better or more
accurate than CMYK; I haven't said that. I've said that I prefer RGB
separations, and I've given my reasons why RGB separations make more
sense to me than default CMYK, but if anyone has taken those remarks as
personal criticisms of their own choice, then they've read way too much
into what I've said.
Katharine Thayer

Joe Smigiel wrote:
> One of the things I picked up on from a post a few days ago is that this
> RGB vs. CMYK "debate" has been going on in some form or another since at
> least early 1999 on this list and has included several of the current
> participants. In that time, a lot of bickering and bad feelings have
> occurred and even resulted in people actually unsubscribing from the
> list as a result of this "debate".
> It would seem to me that the simplest way to settle this is to actually
> make some gum prints comparing the two methods and I have asked several
> times for such a print comparison. But, apparently it is easier to post
> theoretically ad nauseum for 5+ years on this subject rather than take
> the short time needed to make a couple gum prints.
> FWIW, since I made the original comparison request about a month ago I
> have hands-on instructed two novice gum printers on the CMYK method
> (default SWOP settings in Photoshop CS) with a contrast correction curve
> applied to the separate channels before output to Pictorico OHP on the
> Epson 2200. I have again witnessed the apparent superiority of this
> method as they made their initial gum prints. Let me repeat that with
> emphasis: absolute novice gum printers were able to make what I would
> call highly accurate 4-color gum prints using the CMYK method and
> neither had any previous experience whatsoever with gum printing!
> Perhaps it is dumb luck. Perhaps my correction curve somehow
> miraculously affects the outcome in a way I don't understand. Perhaps
> my pigment choice unknowingly skews the results. In any event, I have
> just witnessed another instance of the quality one is able to achieve
> with the standard CMYK separation settings making gum prints. (I'll try
> to get permission to scan and post the new prints next week.)
> As a result, I remain absolutely and totally unconvinced that the RGB
> method is superior to the CMYK method based on the actual prints I have
> made and seen made. No amount of talk will convince me otherwise.
> Prints will convince me.
> Joe
Received on Sun Dec 5 02:06:44 2004

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