[rescue] Risks of lossy algorithms - was Re: Scanning Best Practices - was Re: Inside Solaris newsletter

Toby Thain toby at telegraphics.com.au
Sun Oct 5 21:25:29 CDT 2014

On 05/10/14 9:59 PM, Jonathan Patschke wrote:
> On Thu, 2 Oct 2014, Toby Thain wrote:
>> 3) Be very careful with DJVU compression - it is lossy! - the results
>> can be surprisingly dangerous. I can't find the link now, but there
>> are published examples of schematics involving substituted numbers
>> (literally one digit for another). It's clearly a risk derived from
>> the way djvu works. Use lossless TIFF LZW or similar.
> My understanding is that those instances are from defects in Xerox
> firmware, not from the design of djvu.

Perhaps - but I am not sure it's possible to rule this out in any djvu 
implementation. Do you happen to be able to find the original citation? 
I couldn't find it in a few minutes' googling.


 > Still, as a general, rule, do not
> use lossy compression for archival.  Data are precious; do not discard
> them!

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