Thousandth data book uploaded to bitsavers
cisin at xenosoft.com
Fri Jul 14 14:55:27 CDT 2017
>>> Many databooks I find are printed on the fragile "telephone book" type
>>> paper, either transparent, beige or both. Do you have any techniques
>>> for getting good images out of those, and making sure they survive the
>>> trip through the ADF?
>> Always scan those monochrome. (A lot of people insist on color
>> scanning of black and white materials)
On Fri, 14 Jul 2017, Paul Koning wrote:
> You mean grayscale, right -- not bitonal. I sometimes scan on
> copier/scanner units because they happen to be available, but they are
> often bitonal and produce images with lots of black noise pixels. With
> grayscale scans, you can avoid those by tweaking the threshold and/or
> adjusting the curves.
Although SOME scanners have good threshold levels for bitonal.
What I object to is people who insist on 24 bit color with lossless
compression. We are after the information content here, not a study of
paper texture and analysis of aging/deterioration.
Sometimes a lossy compression will try to delete some of the noise,
whereas a lossless compression will retain it.
"Doctor Marty" (formerly Coco) runs a large project digitizing some
periodicals from the 1920s and 1930s.
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