This is what I thought, too, but before venturing to say so, I actually
performed an experiment, repeatedly saving the JPG file at the same
compression factor. It got smaller by about 2% each time I saved it. It is
probably honing in on some optimized compression at that level of quality.
Visual inspection couldn't detect any degradation.
Frank Paris
marshalt@spiritone.com
> -----Original Message-----
> From: owner-filmscanners@halftone.co.uk
> [mailto:owner-filmscanners@halftone.co.uk]On Behalf Of Laurie Solomon
> Sent: Thursday, March 29, 2001 8:57 PM
> To: filmscanners@halftone.co.uk
> Subject: RE: filmscanners: File format
>
>
> >Each time there would be some generational loss.
>
> Not necessarily true. If you open and close ( or resave) the
> compressed file
> without changing the compression from one quality level to another in the
> case of .jog or without resampling the image prior to closing or resaving
> the file, there will be no more degradation than opening and closing or
> resaving a raw uncompressed file.
>
> When you open a compressed file you have uncompressed it, so resaving it
> with the same compression as before or without engaging in any resampling
> prior to resaving the file should not result in any additional losses in
> data or quality.
>
