Red Hat Bugzilla – Bug 569564
Unable to calibrate scanner: tiff not recognized
Last modified: 2010-03-04 07:33:41 EST
Created attachment 397144 [details]
I scanned in my IT8 reference card and saved it as a tiff file, however gcm does not like the file and insists that it has to be "an RGB tiff file".
The tiff itself can be opened by other apps just fine and I don't see a way to tweak any settings in Xsane. Re-saving the image in gimp does not help.
Can you attach the tiff file please. Thanks.
Created attachment 397149 [details]
There's the tiff as saved by xsane. The scanner seems to be a bit broken and dusty (which explains the very bad quality) but that should not affect the basics I guess...
FWIW I tried to scan with the gnome scanning tool first but a) it crashed every time and b) it didn't seem to offer saving as tiff at all, so I used the old xsane...
The problem is that your TIFF file contains an alpha channel (RGBA) and isn't RGB, and the argyll tools are very strict on what formats they accept. I've added the following code to GCM git master to fix things up:
Author: Richard Hughes <firstname.lastname@example.org>
Date: Tue Mar 2 10:17:26 2010 +0000
Check and correct TIFF image files with alpha channels before using them in argyllcms. Fixes rh#569564
Could you please check with git master, and verify the bug is fixed (I generated a profile using your target image just fine a few minutes ago).
Ah... well xsane always seems to save as rgba. After manually removing the alpha channel in gimp the calibration works. [I will test with HEAD on my next build]
Off-topic: when using the generated profile from xsane, it didn't seem to work with the icc profile because it contained spaces:
lcms: Error #12288; File '/home/mimox/.color/icc/GCM' not found
Xsane bug or lcms bug?
(In reply to comment #5)
> Ah... well xsane always seems to save as rgba. After manually removing the
> alpha channel in gimp the calibration works. [I will test with HEAD on my next
> Off-topic: when using the generated profile from xsane, it didn't seem to work
> with the icc profile because it contained spaces:
XSane bug. If you file it / fix it can you please cc me. Thanks.
I just tested the automatic conversion using the latest g-c-m and it seems to work. I just wonder if it is really necessary to display the intermediate "conversion" dialog. Is there anything that could go wrong here?
(In reply to comment #7)
> Is there anything that could go wrong here?
Yes. If the scanning software set the alpha to 0.5 to "correct brightness" without touching the RGB values and we just ripped it out, and the profile wouldn't be accurate. To be honest, I'm just covering my own back here.
Ah, that's bad then... would be nice to finally have a working gnome-scan and be able to use it from gnome-color-manager directly...
AFAIK, it's on the gnome-scan/easy-scan TODO list.