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

From: Bob Washburne (
Date: Thu Dec 14 2000 - 08:18:34 PST

  • Next message: Ian Stirling: "Re: Which scanners REALLY provide 36 bit output? HP?"

    Hi, it's me again. The original poster. :-)

    Steve Underwood wrote:
    > Stephen Williams wrote:
    > > And none of this is good news to someone who wants to create archival
    > > images of precious documents. We've been there, too, and the conclusion
    > > is that for all but the most extreme cases, good ol' 12bit JPEG (and an
    > > environmentally controlled vault) are about as good as is worth the
    > > effort. If some hot new image processing technique comes to light, you
    > > are just going to have to accept the reality that you will need to open
    > > the vault and rescan the document with the lighting/sensors required
    > > of the technique.
    > If you want to do archival storage of documents, do it on paper. This will
    > greatly outlast any digital storage medium.

    Erm...,no. Not in this case.

    Much of the paper in question is already on its last legs. The problem
    is with acid paper and embrittlement. Rule of thumb - if it is less
    than a hundred years old, it will not be around a hundred years from
    now. Modern acid-free paper excepted.

    I have taken some preliminary precautions such as haveing many of my
    more precious books de-acidified. But other documents are either not
    worth draconian efforts, or it is just too late.

    My worst case is a wonderfull collection of old Sci-Fi pulps my mother
    got from her father. This is a collection of Amazing Stories, Fantastic
    Adventures, Analog, etc. from the late 1920's through the 1950's. In
    one sence, the collection is priceless. Many of the stories were never
    republished and will die with these magazines. It has been said that
    only 20% of the silent films are still in existance. The rest are
    lost. I suspect I may have the opportunity to salvage a significant
    chunk of history.

    Two major problems; I don't have access to the collection and probably
    won't until my mother passes away (maybe 20 years). Second, they are
    printed on the worst of the pulp paper and are well underway to
    embrittlement. I suspect that when I finally get to them I will have
    one opportunity to open each page and scan it before it crumbles. So
    there will be no going back to rescan with future technology.
    > CDs can fail in as little as a year
    > (any make) despite the claims of 25 years for a pressed CD (which isn't that
    > impressive anyway) and 70-100 years for CDR (which seems completely bogus). I
    > live in a sauna, and things tend to fail fast, but even in dryer climates you
    > can never rely of any digital medium. Some years ago in the UK we stored
    > precious reels of data tape in a fully controlled environment to the makers
    > (Ampex) spec. In just two years the layers of tape had coalesced so well we
    > could saw through the block of tape like it was a block of wood. Of course such
    > extreme failure doesn't always happen. However, since you cannot tell when it
    > will, you cannot rely of these media. Close monitoring and recopying seems a
    > useless precaution, when degradation can occur so fast.

    So far I have not experianced the problems you have. Yes, back in the
    early 80's I had a large batch of nine-track tapes which went bad
    (Graham Magnetics). We switched to Scotch Black Watch and never had a
    problem since. I have yet to have a pressed CD go bad on me and the
    only CD-R to fail has been the dirt-cheap generic.

    There are other philosophical problems to using digital media for
    long-term archives. Accessability. My 8" floppies may still be
    perfectly readable, but can *YOU* access them? You need:
    1) Hardware to access the media.
    2) Software to read the media
    3) Software to interpret the data (JPEG, TIFF, etc.)
    None of which is guarenteed from decade to decade. And none of which is
    apparent from eye-balling the media (can you determine what the format
    of the data is on an unknown media?)

    But there are great advantages as well:
    1) Ease of copying.
    2) No loss of signal from copy to copy. Once a pixel is digitised into
    a "5" that 5 remains a 5 no matter which generation copy it is. And a
    weak five will copy to a strong five.

    Perfection is not attainable, but by aiming for it we just might achieve
    excellence. Color is an empherical beast. Just what is the color of
    the planet Pluto where the sun is mearly a bright star? But given
    sufficient raw data to work with color can be manipulated anytime after
    the fact.

    So this is my stratagy for the poor-man's archive:

    1) Digitize with as much precision as possible (technicly and
    financialy). My baseline is 1200 dpi and 12 bbp per "gun". More would
    be nicer. I am not interested in how it looks - that can be manipulated
    at time of display. I want to capture as much information while I can.

    2) Store on well established media in a recoverable format. I will
    probably use three formats: 1) raw. Just the pixel data in a flat file
    so that any Comp 101 student could write a program to read it. A
    cryptographic checksum should be included to detect degradation. 2)
    ECC. Stored with some sort of hamming code to detect and correct
    dropped bits. The algorithm would have to be included as flat ASCII.
    3) Popular Compressed. JPEG, PNG, etc. for easy viewing.

    3) Publish. Make several copies of the CD's, DVD's, whatever and send
    them to my relatives for off-site storage. We are a wide-spread family
    inhabiting Minnasotta, Indiana, California, Pennsylvania and Georgia.

    4) Publish. To the Internet. Try to find mirror sites for the data of
    historical significance. Copyrights become less of a problem as each
    year more works enter the public domain.

    5) Publish. I am slowly building a family history which spans over 36
    generations and extends back to the original invasion of Normandy by
    Rolo the Viking in 911 AD. Once collected and written it could easily
    become a multi-volume work. Get this printed - with all of the photos
    included - and donated to as many libraries as practical.

    6) Reprint. As the current media, e.g. CD, becomes obsolete and a new
    media becomes mainline, e.g. DVD-R, copy the data onto the new media and
    re-publish. This is where the ECC (Error Correcting Code) format
    becomes important.

    7) Find a child or grandchild interested enough to carry on after me.
    Otherwise, the published versions in the libraries will have to suffice.

    At this point I will probably just keep my HP5370C unless someone
    responds VERY quickly that there is a much better choice out there. It
    has the 1200dpi, no problem. It has 14 bit A/D's and while the included
    software only returns a gamma corrected 8 bits, tech support swears that
    the hardware can return 12 bits to the computer.

    What this means is that I will have to start digging into the driver and
    work with the author of the avision backend to get this to work. And
    the USB driver... <sigh> But then, I knew the job was dangerous when I
    took it.

    Thanks for all the input.

    Bob Washburne

    > Regards,
    > Steve

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