Re: Digital Negs - RGB vs CMYK

Michael,
As far as color separations for gum, I've been working on a web page on
this topic for a couple of weeks. I'm working on it in small bits of
time when I can manage it, and unfortunately don't yet have the tricolor
gum demonstration prints that will eventually support the technical
information, but I still think the technical information by itself may
be useful to you in understanding why I prefer RGB separations. So I've
uploaded the unfinished page for you, with the understanding that
eventually the technical information here will be augmented with more
visuals of actual tricolor gum prints.

http://www.pacifier.com/~kthayer/html/CMYK.html

I don't print tricolors much any more, but for a decade or more I was
known in these parts for my tricolor work and have made hundreds of
tricolor gum prints in beautiful color from RGB separations. There are
only a few of these on my website because my goal there was to show as
many different things that gum will do as possible, and besides I don't
think tricolor is a very interesting thing to do with gum. When I was
trying to explain to a friend why I stopped doing tricolors in 1999, I
said, "They're so......" and she finished, "Obvious? Trite?" Exactly.
But if you're interested, you could page through my galleries; I'm sure
there are a few of my tricolors there that may show that tricolors from
RGB-CMY separations aren't anything like crossprocessed color film. You
can find the links to galleries at

http://www.pacifier.com/~kthayer/

Katharine Thayer

Katharine Thayer

Michael Healy wrote:
>
> Now that the smoke has cleared a bit, I'm going to be rash and stick my neck waaaaay
> out there with a few little quasi-neophyte questions. I want to be clear about something,
> though: I am not interested in getting up people's dander, or getting myself tangled up in
> the age-old argument over which color mode is sacred. I'm interested in understanding -
> for home printers - why there is a differences between these modes to begin with.
>
> Now, I understand the requirements of a printing house: CMYK since Gutenberg. My
> problem, though, is that I happen to print my negs on an Epson inkjet printer that's
> sitting here at my elbow. Okay, so one way I can print my negs - or my separation negs -
> is to leave them as RGB; then again, I can take the trouble to convert them to CMYK
> before I print them. I gather that some people grow hives at the thought of one, while
> others are growing second and third heads at the thought of the other. The whole thing
> gets me totally hung up, though. Here's why: the last time I looked, my Epson was using
> CMYK inks. To my uninitiated eye, it doesn't seem to matter what I do with my file - the
> thing is going to get ripped as a CMYK file, period.
>
> So what is it that I am missing? I can convert a neg (or its separation components) to
> CMYK, and then won't it print as CMYK, unaltered? Or I can be lazy and leave it as
> RGB. Then the printer intercepts it, and converts it to CMYK anyhow, and then prints it
> as CMYK.
>
> So I am wondering about three things:
>
> (1) what difference does any of this make, if the thing has to end up CMYK anyhow?
> Why does it matter what your Photoshop mode is (assuming it is color, not b&w)?
>
> (2) If it is true that both RGB and CMY get turned into CMY by my inkjet printer, then In
> terms of inkjet printing (NOT print shop printing!), what exactly is it that CMYK
> advocates are advocating, that I should take this extra step to convert it? And what is it
> that the RGB advocates are missing, that they think they actually are pulling off an RGB
> print through a CMYK printer?!
>
> (3) GUM! If an inkjet printer does print CMYK, why do people use painter's (RGB)
> colors? It would seem to **require** that one use printer's (CMY) colors - assuming, at
> any rate, that one wants "realistic" colors. How come RGB pigments used on inkjet negs
> don't turn a gum print into something resembling cross-processed C41?
>
> Mike
Received on Wed Dec 1 14:01:29 2004