[argyllcms] xsane color management

Hi,

The purpose of this message is twofold:

1. Firstly, it is meant as a heads up for other people on this list: as of 
version 0.993 xsane has integrated colormanagement. I'd use the latest 
version 0.995 though as there were some issues in the releases inbetween. 
xsane uses little cms for the necessary transforms.
To use color management with xsane, these configuration parameters are 
available:
* use black level compensation or not, together with rendering intent
* an RGB input profile for the scanner
* a grayscale input profile for the scanner
* an RGB display profile
* a proofing profile (beyond my scope currently as I haven't learned about 
proofing yet :-) )
* a workingspace profile. If omitted, sRGB is used by default

I have set the RGB input profile and the display profile. After enabling 
colormanagement, the colors in the preview window shifted, so it seems the 
transforms are working.

For each scan you make, you can choose whether to:
* store the original scanned values together with the scanner profile
* convert the input to sRGB and save without profile
* convert to your preferred working space and save it as such with the working 
space profile.

It all looks very simple and functional to my inexperienced eye.

2. Secondly, I have come across a small annoyance in xsane with respect to 
color management.
I don't have a grayscale ICC profile, so I didn't bother entering it. As long 
as I only make color scans I don't really need it anyway.

But after my experiments, I restarted xsane and I got this error:

Error during CMS conversion:
Could not create transform

When started from the commandline, the above error is accompanied by this line 
in the terminal:
lcms: Error #12288; Input profile is operating on wrong colorspace.

Apart from this, everything seems to work fine. It took me a while before I 
discovered this is the exact same error message I get if I switch 
from "Color" to "Grayscale" as intended scan. This would make sense, because 
I don't have a grayscale ICC profile. Switching back from "Grayscale" 
to "Color" doesn't give me this error.

It appears that when it starts, xsane tries to do something with all the input 
profiles. I think this is a bug in xsane and I'll also let the developper 
know.

But in the meantime, I would like to get rid of the startup error message, as 
I am not the only one working with this scanner.

So basically my question would be: where do I find a grayscale ICC profile ? 
As I have understood, Argyll doesn't support it.
Is there a way to convert a color ICC profile (RGB or CMYK) into grayscale ? 
Or can somebody maybe send me one (possibly off-list) ?

Note that for me, this profile doesn't have to be accurate at all as I don't 
scan in grayscale for now.

In the long run, I may be interested in grayscale scanning as well, so hints 
on how to create a more accurate grayscale profile are welcome as well.

Thank you,

Geert
-- 
Kobalt W.I.T.
Web & Information Technology
Brusselsesteenweg 152
1850 Grimbergen

Tel  : +32 479 339 655
Email: info@xxxxxxxxxxxx

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