# Re: Xsane questions and wish list

Steve Gunnell (steveg@ccis.adisys.com.au)
Fri, 16 Jul 1999 11:59:06 +0800

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Oliver Rauch wrote:

> xsane uses the gamma bit depth the backend uses,
> but the scanner gamma table has to be activated (normally
> by custom gamma table in standard options, but backend dependent)!

I'm just using the default settings. I assumed the scanner was beingchanged
because when I closed xsane and went back to xscanimage
my attempts to correct the white level in xsane were still being applied
to the xscanimage previews. I had to turn the scanner off to clear them.

> Check it in the info window (gamma correction by scanner!)

Will do.

> Ask the backend author about the supported bit depth!

The Photosmart FAQ indicates that at my firmware rev the scannerwill only
return 8 bit values to the host but the A/D converter handles
at least 10 bit values. Lets hear it for crippleware. Maybe Henry knows.

> I will not add such an option in the next time, don`t know if ever!
> For fine tuning use the sliders in the histogram window!

Ummm, okay, see below. Fine tuning is not what I want to do.

> For what do you need the values? In the histogram window

> you have the silders and the color density is given in the
> histogram window.

I'm scanning negatives. So I need to remove the colour mask from the
images.To do that I need to set the white point to the value of the colour
mask. So what
I do is select a scanned chunk of colour mask and average it using the gimp
generic convolution tool to give me the average RGB value for the colour
mask.
If I had a editable value box I could enter these values as the white point
just like
I do with the gimp histogram tool rather than having to mess around with
little
sliders that I can't control accurately. If I could set the colour mask
scaling and
the negative colour inversion once per film in xsane then I can save two
gimp
operations per frame which would be a considerable saving over the 45
minutes per strip of 4 negatives that the process takes now.

> If you want to use values take the brightness, contrast and gamma
> values!

These are no use to me because they are arbitrary values that do not
simplyrelate to the RGB values that I need to change.

If you have a better method for processing negatives that takes advantage of

xsane's features then I would love to know about it.

Thanks,

Steve Gunnell

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