Thousandth data book uploaded to bitsavers

Fred Cisin 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.

Yes.
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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