Re: Digital Negs - RGB vs CMYK

From: Katharine Thayer ^lt;>
Date: 12/01/04-06:56:36 AM Z
Message-id: <>

Katharine Thayer wrote:

> > (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?

I just re-read this and realized, I think, that I answered a different
question than the one you were asking. I thought you were asking why
some gum printers use color separations that they have generated by
inverting the RGB file to CMY rather than converting to CMYK; that's the
question I'm answering with my web page. But your question here seems to
be about printing RGB colors vs CMYK colors on inkjet negs, which is a
different question; as I say I'm not sure I even understand it. Color
separations are in greyscale and are printed either in black ink or in
colored inks to approximate black (at least I don't know of anyone who
is making colorized color separations) the difference is whether the
densitiesof the black on the CMY separations are determined by a
straightforward conversion to CMY from the RGB file or whether the
densities are generated by the default CMYK profile, which was designed
to optimize the performance of a SWOP inks being printed from a
high-speed web-offset printing press on clay-coated paper by altering
the color values from true CMY to accommodate the requirements and
limitations of these commercial printing machines, inks, and papers.
Received on Wed Dec 1 14:52:46 2004

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