Re: colorspace converters

[Keith Packard <keithp keithp com>]

Around 11 o'clock on Feb 6, Raph Levien wrote:
> Many systems (including PostScript) use CIE XYZ as the intermediate
> colorspace when converting between colorimetrically-based color spaces.

Xlib is one such; CIE-XYZ is a pretty good intermediate representation.
Note that Xlib also has mechanism for characterizing the monitor to allow 
for the conversion of a standard color space into device RGB.

Of course, the conversions are simple.  The hard part is what to do when 
the requested color lies outside the device gamut.  Xlib has some 
mechanism for handling this, including the ability to escape back to user 
code for the answer.

One could automatically compute the device characterization from monitor 
DDC information; unfortunately, that's usually so inaccurate that 
selecting some reasonable defaults proves better in practice (sigh).

The only real problem with using sRGB as the "standard" colorspace is that 
it doesn't circumscribe the gamut of all monitors.

keithp keithp com	 XFree86 Core Team		SuSE, Inc.