HP Scanner makes everything yellow

Discussion in 'Scanners' started by Sonnich Jensen, Feb 24, 2012.

  1. Hi

    Here are some pictures:
    http://hot.ee/sonnich/scan1a.jpg
    http://hot.ee/sonnich/scan1b.jpg

    A is the original picture, 50% in order to make it fit here.
    As you can see only a part of it is in the right colours.

    A part of the original scan is the B - with "waves" in it, I have seen
    that before and know simply to resize. But you can see the colour
    difference better.

    What causes the yellowness and how can I fix it?

    It is a HP Scanjet 2400.

    WBR
    Sonnich
     
    Sonnich Jensen, Feb 24, 2012
    #1
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  2. Sonnich Jensen

    Mark F Guest

    Seems like one or more channels cut out. Also looks
    intermittent.

    If you repeat the scan does what looks like a good band
    happen in the same place each time?

    If the good band stays fixed, what happens when you
    move the original on the flatbed (don't worry if some parts
    are no longer scanned): does the good band stay
    fixed on the flatbed or the original?
     
    Mark F, Feb 24, 2012
    #2
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  3. Sonnich Jensen

    Paul Guest

    An image for comparison to the sample.

    http://antikvarhorsnaes.dk/antikvariat/images/uploads/Genvej_over_Nordpolen.jpg

    I don't know why, but the scanned image reminds me vaguely of the example in this article.
    Like I'm looking at a CMYK representation rather than RGB. I'm no "color guy", it
    just looks weird to me.

    http://en.wikipedia.org/wiki/CMYK

    When scanning non-solid color objects (halftones or "dots of ink"), you
    get a moire pattern unless there is "descreening" turned on. The "waves"
    are from interference between the sampling frequency of the scanner and
    the dots in the printed cover.

    http://www.scanhelp.com/288int/artcopy/enterpriseversion/help/images/descreentab.jpg

    There is probably a problem with the image sensor on the scanner, but I'd play around
    with reducing the resolution setting of the scanner, and turning on descreening. For
    close work, sometimes I'd actually use a magnifying glass, to get a better idea of the
    screen print frequency, so I could set the control panel for the scanner a bit better.
    (To reduce Moire, maximally.)

    Also, while the scanner is making the scan, monitor the white light leaking
    around the edges of the scanning bed - check to see if the intensity of the
    like varies as the scan is progressing. Perhaps the light source is not constant.

    As another check, try scanning a 3"x5" or larger print from your
    collection of film prints, as those won't have the same kind of
    halftone issues. That should at least get rid of some of the
    "wave" effect.

    Paul
     
    Paul, Feb 24, 2012
    #3
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