[sane-devel] Re: Re: Re: epson 3490 - transparency unit problem

[plum.pudding at free.fr]

Selon Levente Novák <lnovak at dragon.unideb.hu>:

>
> Two vague ideas (if the green line is vertical):
>
> - defective sensors (maybe a quality calibration would help a bit)

I don't think the sensors is defective, because it works very well on
Windows2000 with the Epson software. And I have try the quality calibration with
no result.


> - dirt on the calibration stripe or windows. Even a small dark spot on
>   the area where shading correction is done could have a big impact, as
>   it gets applied over and over for the whole scan height.
>

This is a possibility. I will check this as soon as possible : in few hours...

Could you explain the calibration process with much details. Is it possible that
the calibration process be different whith snapscan backend than with the epson
software ?
I mean : the position of the calibration is done under the controle of the
firmware, or under the controle of the backend ?


Patrick