Color Spaces - RGB, CMYK, YUV

[Casper Boemann]

On Sunday 05 June 2005 11:39, Bart Coppens wrote:
> On Sunday 05 June 2005 09:08, Casper Boemann wrote:
> > Just to make sure:
> >
> > KisColor should internally be based on XYZ (or lab), but not RGB. This to
> > provide the largest possible gamut.
> >
> > The colorchooser should provide different colormodels for specification
> > but should always store in KisColor and thus in XYZ (or lab).
>
> Why would you want that? Consider that you have XYZ as internal
> representation, and a YUV colorchooser. You want to paint with a certain
> color, so you select it on the chooser. The chooser sets the canvas's
> current color by converting the selected color from YUV to XYZ. You lose
> some precision. Then you want to paint on the current canvas. The brush
> converts the current color from XYZ to YUV. Second loss of precision.
yes precission is lost, but using RGB as internal format looses too PLUS there 
is a real possibillity of going out of gamut.


> Whereas storing KisColor in colorspace dependent format, we have YUV
> Chooser -> YUV KisColor -> YUV KisBrush painting. 0 conversions, no loss of
> precision.
Yes storing in the format of the colorspace of the last storing in addition to 
XYZ is smart. And should be done - no doubt about that. That way you have 
zero loss when no conversion is needed and large gamut conversion otherwise.


But most users won't use a YUV colorchooser, but hsv or rgb and so you have to 
convert.

> Now you could indeed provide some standard colorspace conversions from a
> KisColor to XYZ, but I don't think this should be the default format of
> colors.
It should because it has one of the largest gamuts.

-- 
best regards / venlig hilsen
Casper Boemann