[sane-devel] Epson Perfection V200 Photo - scans White as Blue

[Kåre Särs]

On Saturday 12 May 2012 13:57:22 2cv67 wrote:
> On 11/05/12 23:22, Kåre Särs wrote:
> > With the latest release of Skanlite (0.8), all the settings are saved on
> > exit and loaded the next time you start. So if you change color
> > correction settings they will be the same the next time you run Skanlite
> > (they can be reverted to defaults). I think the relevant options with the
> > epkowa backend is located in the "Scanner Specific Options" tab: Red,
> > Shift green to red, ...
> > 
> > Skanlite 0.8 is packaged with at least Ubuntu 12.04.
> 
> Thanks for that suggestion, Kare.
> 
> I had not heard of Skanlite, but found it OK in Synapt & installed it -
> only version 0.7-2ubuntu3 in my Ubuntu 11.10 though.
> I will try 0.8 when I upgrade Ubuntu to 12.04, but that will not be for
> several months yet (deliberate late adopter to avoid teething troubles).
> 
> Even this version successfully keeps general settings (format & quality,
> save-to-location etc) which is better than iscan at the moment in this
> respect.
> 
> Tone correction was not good though,  for several reasons, at least on
> first attempt (please correct if mistaken):
> 1. Corrections don't appear simultaneously in the preview display, so
> you have to stab in the dark then make another preview to see the result.

The "Scanner Specific Options" are options that are just provided by the 
backend and are scanner/backend specific and not specially handled in any way 
in Skanlite (libksane). 

Gamma correction which is somehow handled could maybe update the preview, but 
there is a big risk that that correction would not be the same as what the 
backend provides.

> 2. After correction (+10% brightness & +10% contrast could be about
> right) then impossible to select the scan area for a document, which
> then appears as numerous fragments...

That sounds like a bug somewhere... could the fragments be automatically 
selected selections? Automatic selections can be cleared through the right-
click menu of the preview. Automatic selections can be disabled in the 
settings in 0.8.

> 3. Correction settings not retained (in this version).
One possibility is to compile from sources (it is not difficult). 

# Install build dependencies 
sudo apt-get build-dep skanlite

# get the latest sources
git clone git://anongit.kde.org/skanlite

# build it
cd skanlite
mkdir build
cd build
cmake -DCMAKE_INSTALL_PREFIX=/usr ../
make

# Install
sudo make install

If you get problems with the above, mail me off-list.

> 
> Another problem is that the only dpi options are 300/2400/4800dpi, so
> only 300dpi really for routine-size scans.
> This is another subject, already open, but not fixed, here:
> http://lists.alioth.debian.org/pipermail/sane-devel/2012-April/029713.html
> 
> Overall, no scanning application I have tried yet in Ubuntu could get
> even an 'acceptable' rating for this scanner, which is not really old or
> exotic, is it.
> Pity...
> 

/Kåre