Message-Id: <mailto:199503202152.PAA16650@library.wustl.edu> Date: Mon, 20 Mar 1995 16:04:01 EST From: Owen <mailto:Somerset@INTERRAMP.COM> Subject: Re: Microfilm Digitization To: Multiple recipients of list IMAGELIB
>Message:
>> I'm curious why you don't just SCAN the source material using a 8
>> bit scanner giving you 256 gray level steps, and then make raster
>> com for the archive?
>
>Because COM does not meet even the basic standards for preservation
>quality microfilm, specifically the RLG Guidelines for preservation
>microfilm. Our greatest concern is the longevity of the master
>negative, when -- if properly processed and stored -- should last at
>least 500 years. COM does not have that lifespan or quality. Nor
>do digital scans of the same images. As Rothenberg states in his
>January 1995 Scientific American article, "It is only slightly
>facetious to say that digital information lasts forever--or five
>years, whichever comes first."
>-Lee Dirks (Preservation Resources, Bethlehem, PA (800) 773-7222)
Lee,
I guess I'm a little confused. When we investigated Graphic COM and talked to all 3 vendors, we came to understand that we could put the same film in the COM units as we use in our DOC II's & III's when we created archival records for a U.S. Gov't agency. As for quality, it is a matter of what you pay for. If you measure image quality by line-pairs / mm then original microform will measure higher than COM. If on the other hand, you use 400 dpi for your scanning and making COM, then by measure of readablity, it will be difficult to tell the difference. (Or you could scan at 600 and then make COM at 300.)
YMMV
Owen.
/********************************************************************\ |Owen Mitz, President, Somerset Systems (301)-807-1686 |
|Specializing in Imaging, Optical Publishing, BPR and Large Databases|
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