[sane-devel] Rendering Intent for Color Management in XSANE Setup

[Stephan Maier]

Hello,

I have been verifying the Color Management in XSANE.
I found a clear discrepancy between the profiling results
achieved with XSANE and the Argyll (www.*argyllcms*.com)
converting routine cctiff. The Argyll profiling results
agree perfectly with the expected values for my target image.
I was able to reproduce the XSANE results with Argyll's cctiff
by using the same rendering intent, i.e. perceptual, for both input
profile (XSANE: Scanner default color ICM-profile) and output profile
(XSANE: Working color space ICM-profile).

This leads me to believe the Rendering Intent choice in XSANE setup
applies to both in input and output profile. This approach is not correct,
however. The rendering intent of the input profile, which corrects errors
of the scanner, has to be set to "Absolute colorimetric", since all other
choices perform a white point correction. XSANE lacks the option
to set this rendering intent independently of the rendering intent
for the output profile (typically the desired output profile intent is
perceptual or relative colorimetric).


Stephan Maier