CMYK Color in OGPro

[Clinton C.MacDonald]

Dr. Sanchez:

On Sep 17, 2004, at 2:01 PM, Edwin Sanchez wrote:

> I am using OGPro to make graphic illustrations that I publish with my 
> manuscripts. The publishers almost always ask for CMYK color. [...]

(I could be making factual errors in the following response, but I 
think the overall gist is correct.) I assume you are submitting 
manuscript figures electronically to the journal's printing house. In 
my own limited experiences with these situations, it is best to let the 
printer make the CMYK conversions. Talk to the journal editor and the 
printing house about this, and be sure to send your own printed copies 
that match the final colors you want as closely as possible.

The majority of the computer graphics programs available to us normal 
users "see" the world in RGB color -- our monitors are synchronized for 
RGB, our inkjet printers take their instructions in RGB, and so on. 
Printing houses used by most scientific journals see the world in CMYK. 
Converting what we see on the screen in RGB color space to CMYK color 
space is a sophisticated process that requires spectrophotometric 
synchronization of the monitor color profiles with the exact output 
device that will be used in the printing. In my experience, you and I 
are not equipped to make this conversion, but a good printing house is. 
Even Adobe Photoshop, which has a toggle to change RGB to CYMK, does a 
very bad job of this conversion.

We recently published a manuscript with several color figures. The 
journal's editors were working closely with the publishing house to 
make the transition from accepting figures only in CMYK to accepting 
figures in RGB, and we were the first test case. The initial color 
proofs the printer sent us were terrible, not matching the colors of 
the inkjet-printed originals at all. However, when we described the 
problems to the printer (too much green, not enough detail in the 
shadows, etc.), the next proofs the printer sent us were *perfect* -- 
the printer had tweaked their color profiles just right. It is my 
impression that the scientific printing houses are being dragged, 
kicking and screaming, into the computer art age, and are finally 
accepting RGB files, which they can then convert to CYMK in-house.

Good luck!

Best wishes,
Clint

-- 
Dr. Clinton C. MacDonald | <mailto:clint DOT macdonald AT ttuhsc DOT 
edu>