I think it is not very true, for the same JPG file if you open it and
re-save it again at the same compression level, the loss is very very
little, I learn this from a book for Photoshop 2.5 many years ago. I
remember there is a feature in Photoshop that can compare the
different between two pictures, the author open and save a file seven
times and found the different between the first JPEG and the last one
has only very little different.
C.H.Ling
Conrad Vogel wrote:
>
> I would warn against saving ANY archival scans with the JPG format. It
> is a lossy format which compresses the pixels when saved by averaging.
> Then every time you open a JPG and save it again, it compresses
> (averages) the pixels once more. files can quickly become "blocky".
>
> Use a TIF or a PNG for archiving. They are lossless - meaning you never
> lose informaion by saving and resaving. When you want to send a copy to
> someone or put it on the web, save it as a JPG.
>
> Conrad
>
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