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

From: Joe Smigiel ^lt;[email protected]>
Date: 12/05/04-12:27:54 AM Z
Message-id: <>

>>> 12/05/04 1:54 AM
"the apparent superiority of this
method "

compared to what?>>>


CMYK digital negatives (on Pictorico OHP from an Epson 2200 or whatever)
from Photoshop (using the standard default SWOP setting) compared to RGB
digital negatives from the same software and materials used to make gum
prints. And, I use the term "apparent" intentionally since I have not
yet seen any prints from RGB digital negatives that counter that

I'm not arguing that there might be better settings or ways to use
Photoshop to produce better negatives for gum printing. (Nor am I
saying film separations are better or worse nor criticizing anything
you Keith have said or done.) I am taking issue with the fact that a
certain person is criticizing my use or recommendation of CMYK vs. RGB
without prints that prove RGB more accurate. If accuracy is not a
concern, then why is this "debate" even going on? If they have no
interest in gum printing for realistic color or accuracy, then why are
they criticizing at all?

I've not attacked anyone-I've challenged them to produce personal
results or point to examples which counter mine. I've not insulted
anyone nor criticized their prints or methods, yet I continue to have my
test prints referred to as having "weird" colors as if there is some
flaw in my testing method and comparison between RGB and CMYK
separations, everything else equal. Those comparison prints are online
for all to see. So, what's the flaw in my testing method? Why are my
prints from CMYK negatives so much better than the RGB ones? Same
Bat-time, same Bat-channel. Here's the finished print (of that naked
lady-beware) tweaked with a few more light gum coats:

I'm satisfied with it. The print from RGB negatives isn't even close to
natural color though the same pigments and times were used.

I've also publically asked to be excluded from further posts by that
individual yet my name keeps coming up and that is the only reason I
have rejoined the discussion today. I can see that is a mistake. I
won't make it again after this post. Believe what you will. I know
what works for me.

I initially entered into this by making an innocent recomendation to
someone asking if there was another method of making separations for gum
printing other than CMYK. I've been misquoted and on the defensive ever
since and I'm really tired of it all. Talk is cheap. Just make the
print that negates what I've said. 'K?

And for the record, most of the prints I earlier referred to as having
a blue/cyan bias were generated from RGB and not CMYK negatives as far
as I can tell. Some so far off color they look like tungsten film used
outdoors on an overcast day. So much for theory.

I am able, and my novice students were able to go from scanning an image
to have a very good, realistic and fairly accurate 4-color gum print in
two days without any previous knowledge or experience gum printing using
CMYK digital separation inkjet negatives. Most of that time involved
drying the paper between coats. If we are able to do that, why can't an
experienced gum printer produce a print using 3 negatives (i.e., the RGB
separations) in a similar timeframe to refute my opinion? I fail to see
what is so difficult about that request. If there is an easier way, I'm
all for it. My experience says it ain't so. All I'm looking for is
visual proof rather than a theoretical discussion that just goes on and
on and on and on without resolution.


Received on Sun Dec 5 00:26:05 2004

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