[sane-devel] Reflecta ProScan 7200

[Michael Rickmann]

Am 26.04.2011 23:41, schrieb m. allan noah:
> On Tue, Apr 26, 2011 at 5:17 PM, Michael Rickmann<mrickma at gwdg.de>  wrote:
>> Hi Jan,
>>
>> Am 24.04.2011 00:58, schrieb Vleeshouwers, J.M.:
>>> Hi Michael,
>>>
>>> A short update on a couple of settings (mode normal/quality,
>>> auto-exposure, auto-gamma, and ICE).
>>> For details see:
>>> http://www.stadspartijeindhoven.nl/jv/SettingsAnalysis.ods I'm not
>>> completely ready with all settings yet, but If you
>>> have suggestions for additional tests, let me know.
>> Thanks a lot, I am constantly looking up things in your tables instead of
>> doing test scans under Windows. I have been busy teaching the pie backend
>> 16-bit colours and larger read sizes than a single line. That kept me busy,
>> so I have not done much progress with regard to the interpretation of
>> snoops. But from the practical point of view, I wonder whether GAMMA can be
>> sent to the scanner or has to be handled by software - my native scans are
>> far to dark - it nags - and a preset GAMMA of 2.2 as Windows-Silverfast uses
>> would be just ideal. So far I have seen no indication that the Win progs
>> send any related information over USB. And GAMMA as sent by the pie backend
>> is not accepted by my scanner: IO-error.
> extract the image data from a windows snoop, and see if it is dark too.
>
> allan
Thank you, allan! The snooped image from Windows-Cyberview looks nearly 
identical to the Xsane one with software gamma set to 1.0 (all 
OPT_GAMMAs set to SANE_CAP_INACTIVE in the backend), have a look at 
300q-snoop-cy.pnm and 300q-g10-xs.pnm at 
http://wwwuser.gwdg.de/~mrickma/sane-proscan-7200/status-270411/ . When 
looking at 300q-22g-xs.pnm (sofware gamma set to 2.2 in Xsane) it pretty 
well fits the Windows-Cyberview one in 300q-cy.jpg.
My question is now, whether there is an option for SANE backends to tell 
the frontend that it is unable to do gamma by hardware but would like to 
use a preset gamma as standard. Are there any other backends which 
do/need that?
Regards
Michael