[sane-devel] Colour problem with Canon Maxify MB5150

[Dr Rainer Woitok]

Ralph and Others,

On Wednesday, 2021-06-30 12:07:49 +0200, I myself wrote:

> Ralph,
> 
> On Wednesday, 2021-05-19 18:21:57 -0700, you wrote:
> 
> > ...
> > On 2021-05-19 8:46 a.m., Dr Rainer Woitok wrote:
> > > ...
> > >   - The PNG file from the flatbed clearly showed the original paper hav-
> > >     ing been rather thin, since some colours from the reverse side shone
> > >     slightly through, and the background colour having been faintly grey
> > >     rather than white.   In other words, this PNG file was a fairly good
> > >     copy of the original.
> > >
> > >   - But the PNG file from the ADF did show almost no shine through and a
> > >     more or less purely white background.  Dark colours appeared slight-
> > >     ly darker and light colours slightly lighter than the original.  The
> > >     effect was somewhat similar to using ImageMagick's "-normalize" opt-
> > >     ion.
> > > ...
> > Some of the pixma devices seems to have a completely different engine
> > for generating scans from the ADF compared to the flatbed.
> > For ADF, they return JPEG data to SANE instead of the normal raster data
> > that we get from flatbed.
> > I have no idea why that would be the case but they do use the same sensors.
> 
> I have meanwhile opened a support case with Canon  complaining about the
> low quality of ADF scans.   In their response Canon pointed out that ADF
> (at least normally) is optimized for speed rather than quality and sugg-
> ested testing with  "IJ Scan Utility"  using the various settings of the
> "Advanced Mode" provided by "ScanGear".   So I reanimated my old Windows
> Vista laptop,  installed "IJ Scan Utility" from the Canon CD and started
> it.
> 
> I selected "Document (ADF Simplex)", "A4",  and "Color" in the input and
> "300 dpi" in the output section,  and under "Image Settings" I left "Im-
> age Adjustment" at "Document"  and set "Unsharp Mask"  and "Descreen" to
> "OFF" and "Reduce Dust and Scratches"  and "Grain Corretcion" to "None".
> Hitting "Scan" I eventually obtained file "ScanGear-ADF-Doc.png".
> 
> In the second run I just changed  "Image Adjustment" to "None" (the only
> alternative offered) and scanned to file "ScanGear-ADF-None.png".
> 
> Finally,  I changed the Source to "Platen"  which forced "Paper Size" to
> "Full Platen"  and "Image Adjustment" to "None"  (greying both out), and
> received file "ScanGear-Flatbed.png".
> 
> Here are the file sizes:
> 
>    $ ls -l ScanGear-*
>    -rwx------ 1 rainer rainer  3324661 2021-06-29 15:48 ScanGear-ADF-Doc.png
>    -rwx------ 1 rainer rainer 11142577 2021-06-29 15:49 ScanGear-ADF-None.png
>    -rwx------ 1 rainer rainer 15357308 2021-06-29 15:49 ScanGear-Flatbed.png
>    $
> 
> Files "ScanGear-ADF-Doc.png"  and "ScanGear-Flatbed.png"  are similar in
> size and quality to the files I originally obtained using "scanimage" on
> Linux,  while the quality of file  "ScanGear-ADF-None.png" is comparable
> to that of  "ScanGear-Flatbed.png".   So setting  "Image Adjustment"  to
> "None" in the "ScanGear" GUI  does produce a decent ADF scan  on the MB-
> 5150.   Now we "just" need to get the same result  from the "pixma"back-
> end ...
> 
> By the way: On their web site at
> 
>    https://www.canon-europe.com/support/consumer_products/products/fax__multifunctionals/inkjet/maxify_mb_series/maxify_mb5150.html?type=drivers&language=en&os=linux%20(64-bit)
> 
> Canon is offering the source code for both, an IJ Printer Driver version
> 5.40 and ScanGear MP version 3.40, of which the former is even available
> as Gentoo package "net-print/cnijfilter2"  version 5.90.  Would these be
> of any help?
> 
> Sincerely,
>   Rainer

However, up to now I never received an answer.  Did I just miss it or is
there really nothing  to be done  to make  _scanner access now easy_ for
the Canon Maxify MB5150?

Sincerely,
  Rainer