Computer Graphics with Photoshop - RGB to CMYK...HELP !!!

Author

RGB to CMYK...HELP !!!

mark4man

2005-08-25, 7:16 pm

People,

For all the photo images I used for a 16 page Insert Booklet design for
my upcoming CD release (which started out their life as RGB's), I
used Photoshop 6 for processing (processing RGB's as RGB's, as
Photoshop recommends)...& then I converted them to CMYK (also in
Photoshop 6.) Then I placed these converted images into the Adobe
Illustrator (10) design templates provided by the replication service,
finalized everything; & sent them off.

Today I got the proofs back from their print division; & all graphic
content is DARK & GREEN !!!

I contacted the graphic arts dept. at the replication service; & they
told me they could color correct them at their end, based on the color
prints I sent them...but when I learned the cost...I thought it might
be best to just do it at my end.

1) First of all...what happened? The photos looked great in both
Photoshop & Illustrator on my monitor as RGB's. When I had converted
in Photoshop, there was no difference at all in appearance. My working
spaces in Photoshop are all default; & the photos look just like they
do on my monitor when they print out in my project studio (on a typical
HP Ink Jet.) I don't mess around with Adobe Gamma or calibrating my
monitor (because...the images on my system look exactly as they do in
real life...so, why calibrate the monitor to match the commercial
systems, which would make every image on my system dark & green...in
which case I'd have to adjust them all back to real life colors, which
I already have now!!! To my mind, the conversion process should be set
up to exactly match the 4 color standard...calibrating the monitors to
match print output is XXX-backwards.) Anyway, It's gotta be something
else.

2) How can I fix this problem? Is this common? Is there some other
way to go back & convert the RGB's, or is there some criteria I can
use to color correct them in their present state as CMYK's? Does
Paint Shop Pro do a better job of conversion (with their "split
channel" thing)? It's very frustrating...all I want is for them to
look like they do on my monitor & as printed by my printer. Now...I
have to put the graphics portion of my CD on hold while this is getting
sorted out...which pushes back my release date.

Will be appreciative of any help,

mark4man

hpowen@operamail.com

2005-08-25, 11:15 pm

Get yourself a Pantone Process Guide
(http://about.pricegrabber.com/searc.../search=pantone)
and compare what you see on your monitor to actual swatches of CMYK
printed on coated stock. For the most telling result, use the guide as
a reference and create some swatches in Photoshop (CMYK mode) using
values from the guide. For relevance, pick colors from the Guide that
are similar to the colors in your images.

My bet is that you'll find your system in nowhere close to being in
sync with your printer's system. Guess which one will have to change?
The fact that your unprofiled monitor and printer agree is a fluke and
means nothing.

hpowen@operamail.com

2005-08-25, 11:15 pm

BTW, a conversion from RGB to CMYK is not a standard "one size fits
all" sort of thing. The conversion has to be done with a specific
output device and a specific output media in mind. Each has its own
characteristics and those characteristics are accounted for in a good
color profile.

In order for Photoshop to make an accurate conversion, it has to map
the colors from one space to another. Believe it or not, your monitor
profile is a part of the process. Since you haven't bothered to profile
your monitor...

tacit

2005-08-26, 4:14 am

In article <1125006145.965125.79670@g14g2000cwa.googlegroups.com>,
"mark4man" <sonic.max@verizon.net> wrote:

> 1) First of all...what happened? The photos looked great in both
> Photoshop & Illustrator on my monitor as RGB's. When I had converted
> in Photoshop, there was no difference at all in appearance. My working
> spaces in Photoshop are all default; & the photos look just like they
> do on my monitor when they print out in my project studio (on a typical
> HP Ink Jet.) I don't mess around with Adobe Gamma or calibrating my
> monitor...

That's the problem.

> (because...the images on my system look exactly as they do in
> real life...

Your monitor is too light and too red. You are not seeing the pictures
as they really are. You may think they look like "real life," but that
may be because coincidence has entered the picture.

> so, why calibrate the monitor to match the commercial
> systems, which would make every image on my system dark & green...

Because for the purpose of reproducing something on a printing press,
that commercial system IS real life. If you don't match the offset
proof, you don't match real life.

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