[sane-devel] Problem with new Canon iSensys MF746Cx

[Andrea Croci]

Hi Kelly,

no, I'm not scanning text for OCR, I receive some documents per Mail
that I need to sign, scan and send back. When the document is printed on
both sides, the back side shows up if I don't adjust the brightness. I
haven't tried to process it in the PC, though. Maybe that works too.

I would love to force the scanner to not auto-adjust, but I don't know
how to do that. Or how to force it to auto-adjust for that matter. All I
know is that with my Epson printer/scanner and the epkowa backend I have
a lot of options including adjusting the brightness. If I set that to a
value between 30 and 40 I don't get the back of the document to show
through. I would like to be able to do that in the new scanner as well.

All I use Imagemagick for is the conversion of the huge .tiff out of the
scanner to a still big, but acceptable in most cases, .pdf.

On 08.09.20 16:53, Kelly Price wrote:
> I take it you're scanning text for OCR?
>
> Consider it line art, and take some advice from Sean Michael Robinson
> in the Cerberus The Aardvark Restoration Project.
> http://momentofcerebus.blogspot.com/2017/02/paper-to-pixel-to-paper-again-part-five.html
>
> In short:
>
> * Scan in 24-bit color.  It doesn't slow it down.
> * Set the brightness/saturation/contrast/gamma to the defaults, and
> don't touch 'em.
> * Force the scanner to not auto-adjust.
> * Your PC is better at adjusting the color values and forcing it to
> greyscale than the scanner is.
>
> To which I add:
> * ImageMagick and some shell scripting can bulk-process anything.
>
>
> On Tue, Sep 8, 2020 at 10:32 AM Andrea Croci <andrea.croci at gmx.de> wrote:
>> Hi Alexander,
>>
>> thank you for your reply. That did work indeed: the scanner gets
>> recognised as 'airscan:e0:Canon MF745C/746C'. However the list of
>> options for that device is very short. For instance there is no
>> "brightness", which would be very helpful when scanning a page printed
>> on the backside too. That's what I always have to adjust with the Epson
>> scanner in order not to see the back printing through.
>>
>> In addition I just checked in my laptop, which has Ubuntu 20.04
>> installed instead. That has recognised the scanner automatically with
>> the "escl" backend. I don't see an "escl.conf" in my desktop with 18.04.
>> Is this just a matter of sane-version?
>>
>> Is there any way to activate other functions for the scanner?
>>
>> Thank you and regards,
>>
>> Andrea
>>
>> On 08.09.20 12:30, Alexander Pevzner wrote:
>>> Hi Andrea,
>>>
>>> On 9/8/20 7:20 AM, Andrea Croci wrote:
>>>> I have just installed a new Canon iSensys MF746Cx on Ubuntu 18.04 and I
>>>> can't get it to scan. It' connected over the network. I haven't found
>>>> any driver or software for scanning on Canon's Website, so I was hoping
>>>> I could do it with sane. I have read on the list of supported devices
>>>> that the MF741/743 are fully supported by the pixma backend.
>>> The sane-airscan will probably work for you:
>>>
>>> https://github.com/alexpevzner/sane-airscan - the project page
>>> https://download.opensuse.org/repositories/home:/pzz/ - binary
>>> packages for many distros
>>>
>