Re: Digital Negs - RGB vs CMYK

Mike,

The primary reason to keep files in RGB when doing standard color printing
with inkjet printers is that if you send a CMYK file to an Epson printer, the
driver will first convert it to RGB, because that is what the printer is
expecting. Thus you lose some of the integrity of the image file if you convert it
to CMYK first because the file goes through two conversions. Most inkjet
printer color workflows and calibrations are based on using RGB files.

Mark Nelson
Purchase the book @
www.PrecisionDigitalNegatives.com
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In a message dated 12/1/04 1:58:02 AM, emjayhealy@earthlink.net writes:

> 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 02:53:37 2004