[Scribus] Color Management issues

Hal V. Engel hvengel
Sun Jan 14 23:10:40 CET 2007


On Sunday 14 January 2007 02:11, Tino Schwarze wrote:
> Hi Jon,
>
> On Sun, Jan 14, 2007 at 03:27:02AM +0100, jon wrote:
> > > this week, I've come across a color management issue with Scribus. I'm
> > > using 1.3.3.7 on Linux (thanks to mrdocs for the SuSE RPMs!).
> > >
> > > I'm using sRGB as the source profile and EuroscaleCoated as
> >
> > sRGB is not a good source to convert from. It's colorspace is very
> > limited and furthermore it's whitepoint is 6500? K wich is not
> > suitable to convert to Euroscale (5000?K).  The whitepoint shift might
> > be or is to harsh to preserve colors intents.
>
> I'm currently using GIMP for my image work and it has no real CM support
> (to come for 2.4). So sRGB is my best bet, IMO.

At best this is a guess and it depends on the source of the image (IE. the 
device - camera or scanner - used to create the image) NOT what editor you 
are using if it is a photographic image.  For non-photographic images the 
correct profile to be using if it was edited in GIMP (<2.3) and your room 
lighting is close to correct (EI. D50) would be the monitor profile if you 
have one.  In addition using an editor that has no support for CM and/or 
working on a display that is not calibrated (at the very least) and profiled 
means that at best you are guessing what colors and tonalities your images 
actually have.

At this time CinePaint is a much better image editor for color critical work.  
Another good choice is Krita which also has good CM support.  After selecting 
better software the next issue is calibrating and profiling your monitor.  
But I won't go into that now other than to say that you do need to at the 
very least get your monitors color temperature correctly set (close to 6500K) 
and the gamma in the right ball park. 

>
> > If you want to have better results you should convert any rgb to say
> > Adobe RGB (6500?K - but rel. large scale color space) or much better
> > ECI rgb (5000?K, large scale). This is for Europe only, though.
>
> Thanks, I'll give it a try.
>
> > Euroscale Coated is an commonly used but very old and out-of-standard
> > profile.  You might get much better results with the rel. new
> > ISOcoated (ECI) or according, depending on what kind of paper or
> > printing process you want to use.
>
> I know that Euroscale Coated is quite old, but a lot of print shops here
> still say "Euroskala" on their requirements. In theory, I's use
> ISOCoated but in practice, a lot of print shops will look weird at me if
> I say it's ISO Coated.
>
> > But with photographic images I commonly get the best results when using
> > perceptual as rendering intend instead of relative shift (rel.
> > colormetric).
>
> The images are not photographic and some time ago, when I looked into CM
> the first time, I decided that rel. colorimetric was the way to go.
>
> Bye&Thanks,
>
> Tino.



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