[filmscanners] RE: JPG sharpening [was: Color spaces for different purposes]

["Laurie Solomon" <laurie@advancenet.net>]

>However, if you save an image as JPEG using the lowest (least) possible
>compression, the saved version will be essentially identical to the
original
>scan.

I agree with this; but in many if not most cases, the compression level used
or required is greater then the lowest possible amount, ranging from level 6
to level 3 in order to get the file small enough to be an email attachment
or a web site download.

>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.

-----Original Message-----
From: filmscanners_owner@halftone.co.uk
[mailto:filmscanners_owner@halftone.co.uk]On Behalf Of Anthony Atkielski
Sent: Sunday, June 09, 2002 3:36 AM
To: laurie@advancenet.net
Subject: [filmscanners] Re: JPG sharpening [was: Color spaces for
different purposes]


Laurie writes:

> For other than web work, some have suggested
> that saving an image for archival purposes as a LWZ
> compressed TIFF file is the best way to go
> for compression without artifacts.

True--TIFF is lossless, and so it does not create artifacts.

However, if you save an image as JPEG using the lowest (least) possible
compression, the saved version will be essentially identical to the original
scan.  Scans do not contain more detail than a low-compression JPEG can
hold.



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