plustek: Thread: bright colors clipped on scanjet 2200c

Hello, I just compiled xsane and the plustek backend and configured it
for use with my new HP 2200c scanjet under linux-2.4.18.  I
successfully used it to scan a picture, but noticed that the bright
areas were all washed out with white.  Adjusting the contrast and
brightness failed to fix the problem, so I think the clipping must be
occurring before those adjustments are applied.

Is there any calibration that I can do besides contrast, brightness,
and gamma?  Do you have a way to test whether values are being
clipped before those adjustments?

I tested the same picture under Windows with HP's PrecisionScan
program, and the output was unclipped.  Here are the pictures (a
little embarassing - that's me at age 4 :-)

From SANE:    http://www.ks.uiuc.edu/~pgrayson/sane.jpg
From windows: http://www.ks.uiuc.edu/~pgrayson/windows.jpg

The windows scan looks identical to the original photograph - note the
range of colors on my nose and forehead, which are clipped on the SANE
scan.

Please let me know if you have any ideas about how to get the quality
of xsane up to what I get under Windows!  Thanks,

-Paul

I just tried plustek drivers version 0.43-7, which supposedly fix "the
HP2200C stuff."  Don't know what that means.  My bright colors are
still clipped, just as badly as before.  I can easily run a test with
any kind of debugging enabled if someone can tell me how to do it!
-Paul

Paul Grayson ####@####.#### writes:

> Hello, I just compiled xsane and the plustek backend and configured it
> for use with my new HP 2200c scanjet under linux-2.4.18.  I
> successfully used it to scan a picture, but noticed that the bright
> areas were all washed out with white.  Adjusting the contrast and
> brightness failed to fix the problem, so I think the clipping must be
> occurring before those adjustments are applied.

Hi Paul,

sorry for the delay, I've been out for vaccation so far.
Fixed the HP stuff means, that the driver works here for my HP2200C.
Well to be honest, I didn't compare the Windoze results with the ones
I got from the Linux driver so far, but when regarding the results you have,
then I think I should recheck the calibration routines. They're used before
the gamma/brightness and contrast stuff is used...

Give me some time to check this. You might send me the Windoze Registry
entry for the HP, there we can find all necessary settings for your HP2200C.
You can easily export them with the registry tool...

Gerhard

On Sunday, 1. September 2002 20:21, Paul Grayson wrote:
> I just tried plustek drivers version 0.43-7, which supposedly fix "the
> HP2200C stuff."  Don't know what that means.  My bright colors are
> still clipped, just as badly as before.  I can easily run a test with
> any kind of debugging enabled if someone can tell me how to do it!
> -Paul
>
> Paul Grayson ####@####.#### writes:
> > Hello, I just compiled xsane and the plustek backend and configured it
> > for use with my new HP 2200c scanjet under linux-2.4.18.  I
> > successfully used it to scan a picture, but noticed that the bright
> > areas were all washed out with white.  Adjusting the contrast and
> > brightness failed to fix the problem, so I think the clipping must be
> > occurring before those adjustments are applied.