Scanning question (Is destruction of old tech docs a moral crime?)

Paul Koning paulkoning at
Mon Jul 22 08:18:12 CDT 2019

> On Jul 21, 2019, at 6:16 AM, Joseph S. Barrera III via cctalk <cctalk at> wrote:
> I'd suggest that in 2019 when bits are cheap and high-quality scanners
> nearly as cheap, "crappy quality digital image" is a bit of a straw man.
> Yes, I've seen plenty of barely-readable or practically unreadable scans,
> but they were made years or decades ago.
> What dpi qualifies as not "crappy"? 300dpi? 400? 600?

That's not a particularly meaningful question.  300 dpi can be adequate, 400 is more likely to be, 600 is plenty for just about every purpose.

But asking about adequate DPI is like asking a race car driver about adequate horsepower.  It's just one tiny detail among a much larger set of more relevant issues.

A high resolution scan with bad exposure, or insufficient dynamic range, can be nearly unuseable.  Post-processing scans to make them easy to read is not at all a simple matter, especially for old faded documents.

You can also cause trouble by a poor choice of compression methods, but fortunately people using scanners typically know enough to avoid JPEG and the like.


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