[sane-devel] Color balancing with a HP ScanJet 3200C

[Francesco Poli]

Hi everybody (again)!

Thanks to Stef's suggestion I managed to get my HP ScanJet 3200C to
work again.  As previously said, it's a parallel port scanner, which
seems to work with the umax_pp backend.
I am using Debian GNU/Linux (testing branch), which includes
SANE version 1.0.19.

I am now trying to get a decent scan quality.

If I scan something with:

  $ scanimage -d umax_pp --format tiff --mode Color --resolution 300 > out.tiff

I get an overly red image, which can be enhanced by correcting the color
balance with Gimp.
I would prefer obtaining a decent color balance by default, though.
I performed some tests, by visually comparing the original paper with
the scanned image (and reading RGB values picked with gcolor2).

I thought that editing {red,green,blue}-{gain,offset} options
in /etc/sane.d/umax_pp.conf would be able to fix my problem.
However, changing those values does not seem to have much effect on the
resulting scan.

Am I failing to understand something?
Can someone please suggest good {red,green,blue}-{gain,offset} values
for the HP ScanJet 3200C ?

I searched the web, but failed to find good hints.

-- 
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 The nano-document series is here!
..................................................... Francesco Poli .
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