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[filmscanners] Re: JPG sharpening [was: Color spaces for different purposes]
"Laurie Solomon" <laurie@advancenet.net> asked:
>>>>>>>>>>>>>>
>Scans do not contain more detail than a low-compression JPEG can
>hold.
This statement I do not understand; please elaborate. Surely, this cannot
be the case if we are talking about raw data as opposed to encoded
compressed data even at the lowest setting in which there still is some
compression of the raw data.
<<<<<<<<<<<<<<
The raw data is not truly random data. It is actually smoothly changing
nearly continuous data. So there is a lot of room for lossless compression.
Low-compression JPEG is very close to lossless compression, and only loses
information in areas of high detail and contrast. Since raw scan data
doesn't have such areas, JPEG works well.
David J. Littleboy
davidjl@gol.com
Tokyo, Japan
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