Re: Which scanners REALLY provide 36 bit output? HP?

From: Bob Washburne (
Date: Fri Dec 08 2000 - 08:22:34 PST

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    Paul Floyd wrote:
    > Quoting Bob Washburne <>:
    > What are you going to be doing with these images? Visualizing them
    > won't be easy (they're certainly well beyond the scope of most
    > monitors and printers). Unless you're doing research or doing high
    > quality commercial printing, then 1200bpi/36bpp is overkill.

    You are correct. 1200bpi/36bpp is overkill for most visual

    My application is archival. I have a collection of old (about a
    century) documents and photos. They will not be around much longer.
    While it may be impractical to preserve the original document (these are
    family records, not national treasures) it should be possible to scan
    them and preserve their information. Once digitised, they can be copied
    ad infinitum with no loss in quality. CD-R's are now cheap and DVD-R's
    will soon follow.

    The images are of borderline quality. Text is sometimes difficult to
    read. Photos are blurred or smeared. Everything has taken on the
    patina of age. There are some effective software packages out there for
    image enhancement. They can remove red-eye, interpret text and
    generally clean things up. Thirty, fifty years from now I'll bet that
    they will perform magic - removing coffee stains, filling in destroyed
    areas, sharpening a blurred photo.

    But any software enhansement package must deal with the raw data and the
    originals will no longer be around to rescan. So it is imperative that
    I extract as much data as possible now while I still can. Ideally, I
    would like to scan photos down to the emulsion resolution which would
    represent all the information possible. For 19th century photography I
    believe 1200 dpi comes very close to this.

    So I wish to scan at resolutions greater then I can see so that future
    software will have the additional information needed to make
    enhansements which I CAN see.

    And that is part of my fustration. I can't *see* if my scanner is doing
    its job. I must trust that I am getting additional information and not,
    as you correctly indicated, just four more bits of noise. This was one
    of the draws of the HP 5370C. It claimed to be using 42 bpp internally
    and outputting a clean 36 bpp. But the software which comes with the
    scanner is only interested in visual effects.

    Which all leads back to my original question: does anybody have
    experiance with a scanner which shows that it *really* does provide
    these specs?

    Thanks much.

    Bob Washburne

    > Regards
    > Paul

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