Archived from groups: rec.photo.digital (More info?
"larrylook" <LarryLOOK@noemail.com> writes:
> If I start with a picture and save to a lossless format (say TIFF),
> then save the TIFF to another lossless format, say PSD, then save to
> another (say JPEG 2000) etc, etc. Then I resave back to TIFF at the
> end (I've made no alterations or modifications). Is the final file
> identical to the one I started with (or has it changed and how?) Is
> it worse or degraded somehow? All I do is save in a circle (through
> various lossless formats) and come back to the original format. Any
> opinions appreciated.
It'll be identical, if you *really* don't change anything. Don't
change color space, don't change bits-per-pixel, etc. And with TIFF
for example, there are many compression options possible according to
the standard, including some lossy ones; and of course if you choose a
lossy compression method in that situation then all bets are off.
Same with Jpeg-2000; I do seem to remember a lossless option in there,
but *most* jpeg-2000 files use a lossy compression.
David Dyer-Bennet, <mailto:firstname.lastname@example.org>, <http://www.dd-b.net/dd-b/>
Pics: <http://dd-b.lighthunters.net/> <http://www.dd-b.net/dd-b/SnapshotAlbum/>
Dragaera/Steven Brust: <http://dragaera.info/>