> David Fox wrote:
>
> > No problem... I'm currently scanning some very old and deteriorating
> > black and white photographs, and I've noticed a couple of problems
> > with using xsane. First, the range of the xsane brightness and
> > contrast controls is much less than the range provided in scanimage,
> > at least with my HP-3c scanner using the HP back-end.
> >
> > Second, I think I will also need to be able to change the brightness
> > and contrast settings used when acquiring the preview, and see new
> > histograms and perform the usual xsane modifications in relation to
> > those new ``default'' settings.
>
> The birghtness and contrast of xsane is a software created digital gamma
> table and has nothing to do with the options the scanner makes available,
> these are still available in xsane under standard or advanced options!
>
> You can change the scanner brightness and contrast and do a new preview
> scan and see the changes in the histogram.
> I think about adding support for a preview scan with more than 8/24 bits/pixel,
> but I am not sure if that really is necessary.
Oh, I see, I didn't understand the significance of the standard and
advanced options. I think there might be a way to integrate all of
these controls into a unified whole. The use of the hardware's
brightness and contrast to achieve a particular goal is preferable to
the use of post processing. It would also be nice to get immediate
feedback of the effect of changing the ``standard'' brightness and
contrast controls, the way you do with the xsane controls. I suppose
that you could do a some calibration, sampling an image at various
settings and construct a function representing the scanner's response
curve?
Maybe when you stop manipulating the controls it could actually go out
and get a new preview without being asked?
-- David Fox http://hci.ucsd.edu/dsf xoF divaD UCSD HCI Lab baL ICH DSCU
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