Re: Digital Negs - RGB vs CMYK

Date: 12/01/04-10:12:16 AM Z
Message-id: <>

>Mike asked:

>(1) what difference does any of this make, if the thing has to end up CMYK
>Why does it matter what your Photoshop mode is (assuming it is color, not

The Epson printer drivers assume you are printing an RGB file so the
driver is designed to make an intelligent conversion from your RGB image
to the CMYK inks (or with the photo printers, it's more like CcMmYKk
these days) that the printer uses.

There are 3rd party RIPs (Rastor Image Processors) that will let you
control the individual CMYK output. And Epson has just released their own
"Epson Stylus RIP Professional" that probably does something similar.
It's about $200. For most of us, this isn't something we need to mess
with for either making prints or negatives.

>(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?!

I don't know what advantage there is to printing a CMYK image to an
inkjet printer...but there might be some on this list who know.

Keep in mind that making Separation negs is a different beast altogether.
For that, you DO want to split your channels into CMYK (or CMY). Then you
use these separated channels to make monochromatic, individual negs on
your inkjet printer. I don't want to turn this into a sales pitch but I
have 20 pages in my book that talk about this very issue. The mechanics
are somewhat hard to condense down to a paragraph or two. ;^)
>(3) GUM! If an inkjet printer does print CMYK, why do people use painter's
>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?

That's a good question for the gum printers on the list!

Hope this helps!

Received on Wed Dec 1 10:12:54 2004

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