[sane-devel] Canon DR-C225 II - black scan

[m. allan noah]

Marek et al-

I've spent a couple evenings looking at all the various logs that I
have for the C225, and have discovered that it does a different type
of fine calibration from other models. So, I've worked up the attached
patch, against the current sane-backends sources. The idea is to
re-use some of the existing calibration code instead of writing a new
version just for this scanner. I expect this may not work, and if it
does, it will only give us poor quality images. But, it should be
enough to validate that the issue is caused by calibration. You will
need to apply this patch to sane-backends source, and
rebuild/reinstall. I don't have access to any Canon scanners at this
time, so I have only verified that this compiles, unfortunately.

Let me know what you find out, or if you need help.

allan

On Thu, Jul 23, 2020 at 8:53 PM m. allan noah <kitno455 at gmail.com> wrote:
>
> Marek, I'm sorry it has taken me a month to reply, life is a little
> 'different' these days :)
>
> So I have gone back through every email thread I have had about the
> DR-C225, and do have a set of logs from the windows driver. I will
> attempt to determine which bit of magic we are missing. It will take
> me some time, as I am travelling now. If you do not hear from me soon,
> please feel free to reach out. Also, if you want to study up on
> rebuilding sane-backends from source in the meantime, we will need it.
>
> allan
>
> On Fri, Jun 26, 2020 at 4:33 PM Marek <mrupniew at tlen.pl> wrote:
> >
> > Dear developers,
> > I wonder if you could help me with resolving a problem with Canon
> > DR-C225 II scanner (canon_dr backend). The output scan is all black. In
> > 2015 there was a thread on the predecessor of this scanner: DR-C225
> > (without 'II'), which suffered from similar problem. Unfortunately that
> > thread seems to be prematurely abandoned without solving the issue.
> > I'm attaching a scanimage log for a page scanned in a grayscale mode (for
> > the color mode the output scan is black as well).
> > Best regards,
> > Marek
>
>
>
> --
> "well, I stand up next to a mountain- and I chop it down with the edge
> of my hand"



-- 
"well, I stand up next to a mountain- and I chop it down with the edge
of my hand"
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