Re: color model

[Joel Biddier]

el Sismógrafo, S.L. wrote:

> just to get a couple of things right:
>
> - the RGB Gammuth is wider than the one of CMYK (cmyk uses one color more but 
> adds redundancy to the model)
And hence the time old graphic arts problem when computers hit the scene.
Adobe has done a lot on it's products to deal with this very issues - 
it's that important for those who have art work that will cross paths 
with a commercial printer.

Four color (CMYK) process printing  is used by commercial printers (i.e. 
print shops). You can loose color quality if RGB is used (many RGB 
colors don't translate well).
This is what separates professional printing from web and presentation 
output. Granted, I myself  do more presentation stuff, hence, the RGB 
model is fine (CMYK is useless in these cases). Using only a RGB model 
will limit the application use to those who don't print commercially 
(which is perhaps the larger audience, never the less... ).  The user 
would have to know exactly which "safe" colors to use.

When doing art work it is best to start your document in the color 
scheme desired (with the output media in mind). It is not good when you 
convert from one to another - you can get unexpected results.  CMYK is a 
better color scheme for high quality printing (it is how printers work) 
and commercial graphic application vendors know this - and take this 
into account.

> - Have a word with the Scribus folks, they have a lot of experience with the 
> cmyk issue and Scribus uses cmyk model also for saving color values to files.
> Talking about cmyk is talking about a _very_ complex subject.
>  
Yes, and why it might be best to know about it now. Or start 
researching it.

> I think it first has to be clear what Sketch, sorry Skencil, is targeted for 
> before major changes to the core are done.
>
>  
I thought of just that. An my conclusion is:
like Scribus (and most vector appplication and layout application in 
general), I assume Skencil's target is for print - which is best served 
by CMYK in many cases.

Postscript and Latex documents I feel are one of the main targets of 
many Skencil users (end result is most likely a DVI, PS or PDF file. I 
have not taken a pole on this to find out, but the remarks from the user 
group mailing list give this impression - myself as one of them. 
Scientific diagrams and drawings seems to be a big target - again, 
myself included. ). Because most PDFs are electronic based (i.e. viewed 
and maybe printed - and if printed, done so on a "regular" printer, and 
not on commercial and commercial quality printer) most get away with the 
RGB model. Thus, not having CMYK has not hurt Skencil's use much. But 
that is short sighted. The same could be said about Gimp.

My fear is that if we do not implement this now, it may not be easier to 
implement later - I could be wrong - for I don't know all of what is 
takes to do this. My logic is that if it is hard to do now, I doubt it 
will become easier as more code is generated (unless it is completely 
independent of much of the code).

It may not be as important as I think.

Do we change the color scheme to include CMYK? and if so, how and when?
Do we need to change the color scheme of the "skcolor.c" file (RGB with 
a CMYK model build in - a subset deal? RGB that understands which colors 
are in the CMYK gamut?). Or do we do a translation at a higher level of 
the code (given that may not give good results). Again, I don't know. I 
don't know at what level this effects. I only know that the color scheme 
is at a core level of the skencil program (looking at the Modules 
directory).

Seeing we don't know (at least I don't ;-) ), we can over look it for 
now if it puts thing to a hault.  And worry about it later, with the 
uderstanding that it may be a big deal later. If not then take the time...

Perhaps you should just code on. I'll add to my list the task of  
looking up on this topic and see what all it entails. I do know a little 
C (so I should not be completely lost).
Seeing I'm the only one who thinks it important - perhaps I should 
investigate it ;-) .

--J