Re: CMYK separations on Adobe Photoshop

From: Katharine Thayer ^lt;[email protected]>
Date: 11/04/04-06:02:40 AM Z
Message-id: <>

Although this post (below) arrived yesterday I didn't open it til just a
few minutes ago; I wish I had just left it unread. After a quick
reading, I chose to reply only to one part of its content, to correct an
obvious mistatement of fact, and let the rest of it go. I found it very
upsetting, as I simply don't understand the animosity directed toward me
in this post and in earlier posts in this thread by the same person. I
have said earlier in the thread that I certainly haven't meant to offend
anyone by sharing my own observations on this topic; I don't know what
else I can say.

But there is one thing I regret: in an attempt to bring Keith up to
speed on the issues at hand, I characterized Joe's position by
summarizing it rather than quoting him directly. That's not okay; he is
perfectly within his rights to object, and I apologize for it.
Katharine Thayer

Joe Smigiel wrote:
> >>> 11/03/04 4:25 AM >>>
> Keith, I got into this discussion when Joe said that only the CMYK file
> contains correct color information and that color separations from the
> RGB file will give a distorted color balance in a tricolor print, and
> advised that people should always convert to CMYK before printing
> separations. This is not consistent with my own experience, and I said
> so. I suspect Joe still doesn't believe that I can print true color
> (when I want to) from RGB separations, and I haven't found a way to
> prove it for him, so that's just going to have to remain unresolved. <<<
> Not quite. I said in regard to the RGB set: "Be aware that this set of
> negatives will be distorted in terms of color printing characteristics
> compared to those made using the CMYK mode and selecting those
> individual channels for negatives. The info preserved just isn't the
> same, but can be interesting nontheless."
> My statement never puts forth any absolute about which set is better.
> Nor did I ever say that people "should always convert to CMYK before
> printing separations" as you've implied. Rather, I stated a general
> conclusion regarding results of one set relative ("compared") to the
> other based on my experience. The results of my recent test strengthens
> that observation and, at least with the image I'm printing now, confirms
> that my set of CMYK negatives made a more accurate transcription when
> everything else was held constant. In a later post I did say I believed
> CMYK negatives gave more "accurate" transcriptions. Having not seen any
> visual evidence to the contrary (i.e., another side by side test of a
> RGB vs. CMYK set of negatives printed in gum) I still hold that belief.
> I also never said that you personally would not be able to print "tue
> color" when you wanted to from the RGB set.
> Please stop making such unfounded projections and inferences regarding
> what I believe or say.
> I've never claimed to be any expert on this topic and was simply
> relating my experience and what I've read about separations. I offered
> the RGB method as an alternative and did so with a friendly intent and
> attitude in contrast to the critical tone you came back with.
> What I objected to in your reply was:
> "...and since I know of
> several other gum printers who also work directly from the RGB file and
> also get beautiful and true colors, to my mind the general conclusion
> Joe seems to be drawing, that if you print from RGB files you will get
> weird and distorted colors, is problematic because there is so much
> available evidence to the contrary."
> I politely asked for an example of who these "several other gum
> printers" are "with so much available evidence to the contrary." You
> have failed to produce even one example though I've asked twice now.
> And, not that a single test would provide any real resolution to the
> question, but apparently you have two sets of personal negatives to
> compare results yet you state that won't print the CMYK set. Doing so
> would at least add some additional concrete visual information to the
> debate.
> A check of the archives will reveal that gum workers contributing to
> this list get widely varying results using the same materials and that
> the method and materials that work for one person don't necessarily work
> for another. Personally, I don't have very good results with W&N Winsor
> Blue which is a staining phthalocyanine pigment in my experience, and I
> don't believe Paul Andersen's gum-pigment ratio test is valid as stated
> in many texts and which is a belief held by several gum printers on this
> list. I've done the test by the book several times and have always
> arrived at that same conclusion. Others apparently have different
> experiences, results, and beliefs. Fine. No problem. I'm just
> relating my personal experience. YMMV. But, I'm also not taking things
> out of context, making inferences, misquoting other posters, and
> refusing to show my results hoping that some pronouncement I make will
> suffice to convince others.
> Leave me out of your posts in the future.
> Sorry to bother the list with this.
> Joe
Received on Thu Nov 4 13:58:49 2004

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