[scribus] Colour Profiles - make colour matching worse!

Peter Nermander peter at nermander.se
Sat Jul 25 09:37:30 CEST 2009

> Yeh well thats not entirely logical either!  You should be able to output to an industry standard and then tell the printer here's a job thats in industry standard format - use the printer specific profile built into the printer to output the job adjusted for the printer.

The above statement makes me think you don't have the slightest idea
about the problems with color management.

First of all we have the colorspace. The colorspace tells which
physical color (usually defined by CIELAB) a certain numerical value
(as for example the RGB value of a pixel in a JPEG pictore)
corresponds to.

So for example a pixel with values RGB 12:34:56 is one color in sRGB,
but a completely different color in for example AdobeRGB.

Now, CIELAB contains all colors visible by the human eye (as far as I
understand it), however other colorspaces contain only a subset. That
means that for example the colorspace AdobeRGB contains some colors
that CAN NOT be reproduced in the colorspace sRGB. The coverage of a
certain colorspaceis called gamut, colors that can not be reproduced
are "out of gamut" (and Scribus has support for showing you which
colors are out of gamut for the end device, if you have correct

Also RGB and CMYK are totally different. When you tell Scribus to
produce a PDF for print, it creates a CMYK PDF. But from what you are
writing (that your printer is using its built in profile) I think your
printer wants RGB data, so you should create a PDF intended for screen
(the only difference is RGB vs CMYK).

This page doesn't cover everything, but is has links to further reading.

Color management is VERY complicated, and you have to make sure you
understand which profiles are needed for which translation. I know
enough about color management to understand that I shouldn't be using
it yet... I need to learn more.


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