[Radiance-general] Radiance-general Digest, Vol 82, Issue 16

[Greg Ward]

Hi Jelle,

If you are using another system with different RGB primaries than Radiance, you should make sure you are using those in your conversion.  This probably means you want to alter your command a bit:

	ximage -ov input.hdr | rcalc -f xyz_rgb.cal -e 'CIE_pri(i)=CIE_709(i)' -e '$1=179*X($1,$2,$3);$2=179*Y($1,$2,$3);$3=179*Z($1,$2,$3)'

There are a few different primaries to choose from in xyz_rgb.cal -- the default ones are the Radiance primaries, which differ slightly from the CCIR-709 (sRGB) primaries I've specified above.  You can also enter your own primaries if you know them.  Just follow the example in the xyz_rgb.cal file.

Cheers,
-Greg

> From: Jelle Feringa <jelleferinga at gmail.com>
> Date: December 15, 2010 12:27:55 PM PST
> 
>> 	ximage -ov ata/Desk.hdr | rcalc -f xyz_rgb.cal -e '$1=179*X($1,$2,$3);$2=179*Y($1,$2,$3);$3=179*Z($1,$2,$3)'
> 
> What's so cool about this is that with ArgyllCMS & Color Munki ( a very precise spectral measuring device ) you can measure XYZ samples efficiently and with cheap off the shelf hardware.
> ArgyllCMS ( open source ) just totally upgrades the terrible software Color Munki comes with. The hardware itself is very powerful.
> I'm working on printing HDR data, so this lets me cross reference with the original radiance data. Yay.
> 
> -jelle