Re: Problems with Mustek 1200 SP, mode color

From: Henning Meier-Geinitz (hmg-ml@gmx.de)
Date: Wed Sep 20 2000 - 09:52:00 PDT

  • Next message: bob van der Poel: "xsane DOES NOT WORK"

    Hi,

    On Tue, Sep 19, 2000 at 11:53:16PM +0200, Paul Aschenborn wrote:
    > The scanner has a physical resolution of 1200 dpi, color.

    600x1200 dpi to be exact.

    > Black/white and gray
    > scanned images work perfect, I have no trouble at all, but when I switch to
    > color scan, I have some fancy effect I can not use at all.
    > First of all the color dont match with the real ones. The are totally shifted
    > into
    > blue, green or red. Well not just shifted, that I could correct ...
    > The most remarkeable thing about it is, that it is reproduceable and the
    > type of the wrong color depends on the used resolution. So scanning at
    > 120 dpi ist a blue like image without any red scanning with 125 dpi becomes
    > more and more green ...

    That's the "standard" line-distance correction problem. Could you please send a
    debug log to me, I need to know the firmware version and some further
    details of your scanner.

    SANE_DEBUG_MUSTEK=5 scanimage -L 2>debug.log

    Thank you.

    > Additionally I get some "bad lines" in the pictures, they repeat in a constant
    > frequent all over the image. If the image is dark, those lines (1-3 pixel
    > broad)
    > are bright and visa versa.

    These are at the place where the scanner starts a new block ob data. If you
    change the buffersize (option buffersize in mustek.conf) the distance
    between these lines should change, too.

    > Since there are no options in the mustek.conf I tried out so change almost
    > everything
    > I can.

    In mustek.conf, option linedistance-fix should be removed or commented out
    if it's there.

    The problem is probabaly easy to solve in mustek.c when I know the firmware
    version. I had one more report about a similar problem since SANE 1.0.3.

    > The problem is the same with different types of images, different
    > kernels (2.2.14 - 2.2.17)
    > and I even plugged a Adaptec 2490 in. All the same error.

    The error results from different methods to compensate fort the line shift
    of the three color CCD lines. Some scanners do this line-distance correction
    internally, for some this must be done in the backend. So the backend must
    know for which firmware version it should do the correction and for which
    it's not necessary.

    > Then I realized, that the scanner is recognized as Mustek 12000 SP and not as
    > 1200 SP.
    > As far as I know the only difference are some cheaper mechanical parts in the
    > 12000, so I
    > dont know if there is something wrong.

    No, that's OK. They are identical. Mustek's scanner names are quite "funny".
    I have two 1200 SPs, both are labeled MFS-12000SP on the back. One is labeled
    "MFS-12000SP" on the front, the other one is a "1200 SP" (without MFS). If
    you ask the firmware for their name, it's "MSF-12000SP" (not MFS!). Ah and
    yes, a Paragon 1200 SP III would be a total different scanner despite its
    name.

    > At last I got another question: I configured saned to scan via network (this
    > does not affect the
    > problem above in anything - it occurs when scanning on local device and over
    > net ...)
    > Now I did some "scanimage -dnet:computer:mustek:/dev/scanner ..." which worked
    > fine.
    > But scanning with the X-frontends like xsane, xscanimage refused with the
    > message
    > "no device found".
    > How can I teach them to use the network - scanner ??

    Check if "net" is in dll.conf. You can add the name of the backend+device to
    xsane/xscanimage:

    xsane mustek:/dev/scanner

    Does this work?

    The Mustek backend homepage is at http://hmg.home.pages.de/sane/ . You may
    find some tips about the Mustek backend there.

    Bye,
      Henning

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