[Chimera-users] Defining CMYK color scheme for color actions

Greg Couch gregc at cgl.ucsf.edu
Thu Feb 21 21:32:26 PST 2019

CMYK is just an another way of encoding colors.  All of the computer 
graphics uses RGB colors, even if you specify it with CMYK values.   All 
printers print CMYK images, so the printer software does the conversion 
if you don't.  Most publishers now accept RGB images and do the 
conversion themselves because they'll need the RGB version for the web.

Even if the publisher accepts RGB images, to ensure that your images are 
suitable for printing, you should print your images and see how the 
color is different from the screen version.  The color gamut of screens 
and printers overlap, but there are major differences, in particular, 
screens show much brighter colors. Often, things that are obviously 
different on the screen, are not as different when printed.  Then you 
can revise the colors if need be.  And, almost 9% of the population has 
some degree of color blindness, so use your colleagues to test your 
images too.

If the publisher really needs a CMYK image, then you should use Adobe 
Photoshop, or some other image editor, to convert your saved image from 
RGB to CYMK.  To get the printed colors as close to the colors you're 
seeing, you'll need to associate a color profile with the image.  People 
that really worry about color, calibrate their monitors, and use the 
profile generated by the calibration tool.  In molecular graphics, we 
are not such people.  If you don't have a color profile for your screen, 
use the sRGB color profile.  Next, you need to pay attention to which 
version of CMYK your publisher wants.  US and European publishers have 
slightly different versions -- if I recall correctly, the European CYMK 
is better at showing shades of red.  If you are printing the image on 
your own printer, you should use the color profile for your printer 
instead of one of the standard CMYK ones if you have it. Adobe Photoshop 
has a way to view the transformed image on your screen, instead of 
having to print it -- presumably other image editors do too.

Bottom line, give the publisher the RGB image and let the publisher 
sweat the details.

     Hope this  helps,


On 2/21/2019 3:42 PM, Boaz Shaanan wrote:
> Hi,
> Some journals require usage of CMYK color scheme. I see that the CMYK option exists in the color editor but is it possible to define CMYK for all the color actions (actions --> color) without having to go through the color editor for each color? Or am I missing something altogether?
> Thanks for you advice,
>                 Boaz
> Boaz Shaanan, Ph.D.
> Dept. of Life Sciences
> Ben-Gurion University of the Negev
> Beer-Sheva 84105
> Israel
> E-mail: bshaanan at bgu.ac.il
> Phone: 972-8-647-2220
> Fax:   972-8-647-2992 or 972-8-646-1710
> _______________________________________________
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