Overhead scanners

From: Luiz da Camara leme (camara.leme@MAIL.TELEPAC.PT)
Date: Wed May 30 2001 - 11:50:32 CDT

  • Next message: John Warren: "Re: Overhead scanners" 

    Message-Id: <200105301711.KAA17704@dns.ccit.arizona.edu>
Date:         Wed, 30 May 2001 17:50:32 +0100
From: Luiz da Camara leme <mailto:camara.leme@MAIL.TELEPAC.PT>
Subject:      Overhead scanners
To: mailto:IMAGELIB@LISTSERV.ARIZONA.EDU

    <pre>
        Hello everybody:

        I am new to this list. The message bellow was the first I received so far, and this is my first post.

        The reason I subscribe this list its because I have a very special interest in overhead scanners.
        I am thinking about preserving vasts amounts of data and making CD books out of public domain printed books as well as publishing very rare books and manuscripts.

        I don't know much about this but I will be reading quite a lot os messages from this list archives to find out more about this.

        I would appreciate very much any info about solutions for what I need to do. Types of available scanner (I only know 2) software needed, solutions for this purpose.

        Also info about where I can retrieve related knowledge will also be appreciated.

        I am sure this is of no interest to many more advanced members of this list.
        So I can be contacted in private not to disturb everybody else.

        Luiz da Camara Leme

    ----- Original Message ----- From: "Mary Winter" <mailto:mary.winter@MAIL.STATE.KY.US> To: <mailto:IMAGELIB@LISTSERV.ARIZONA.EDU> Sent: Wednesday, May 30, 2001 4:31 PM Subject: Re: information contained in surrogates

    > Our photographer, Nathan Prichard, has been looking over my shoulder on
    this
    > discussion. I include his thoughts on this below:
    >
    > Mary,
    >
    > Well, I see a Hollinger box of weasels has been opened.
    >
    > I derived my very approximate figures based on the normal
    > levels of resolution for various film formats, if the
    > photographer is doing his part. These are the resolutions
    > on the film, which are almost always less than what the
    > lenses are actually capable of producing, if that nasty old
    > physical stuff with emulsion were not involved. Resolution
    > is in line pairs per millimeter (often listed as lines per
    > millimeter or lpm). The lines are separated by a space equal
    > to the width of the line, so the pair actually made up of a
    > black line and a white one (| (sp) | (sp) |). In digital
    > terms, that means two pixels (one for the black and one for
    > white/blank space). So a resolution in lpm's is doubled for
    > pixels (or dots) per millimeter and then multiplied by 25.4
    > (millimeters per inch) for dpi (dots per inch).
    >
    > lpm x 2 x 25.4 = dpi
    >
    > Film size Nominal lpm Approx. DPI
    >
    > 35mm 80 4,000
    >
    > 120 60 3,000
    >
    > 4x5 40 + 2,000
    >
    > [8x10 uses some of the same or similar lenses as 4x5.
    > Resolution would be about the same, at least for many
    > modern lenses. Some lenses can produce greater resolution
    > on some formats, as with macro/copy applications.]
    >
    > Uncompressed file size can be calculated by multiplying the
    > format dimensions (in inches) by the dpi squared for B & W.
    > For color, multiply that result by three (assuming 8 bit
    > color depth in both cases).
    >
    >
    > Nathan
    >
    > I think this is pertinent to the original question about stitching files.
    > Please note, however, that the issue of resolution was not the primary
    > factor in our decision to incorporate analog surrogates into our
    > preservation/access workflow. But then, we have Nathan . . .
    >
    >
    > Thanks, Mary
    >
    > Mary E. Winter
    > Special Collections Manager
    > Kentucky Historical Society
    > 100 W. Broadway
    > Frankfort, KY 40601
    > tel.: (502) 564-1792 ext. 4428; fax. (502) 564-4701
    >

    </pre>

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