Re: GIF vs JPG

[P3D Gabriel Jacob <jacob@xxxxxxxxxxxxxx>]

As Greg Marshall mentions, JPEG is more suited to continuous tone
images. The problem with JPEG is contrasty pictures leave alot of
"artifacts" on the edges between the hi and lo contrasts. So for
these kind of images even at O loss specified in the software I
found it to be noticeable. I guess it could be due to the software
I was using, since it's been mentioned there shouldn't be any loss
at that setting. But even with continuous shaded pics (at O loss)
I also noticed the colors subtley shifted from the orignal colors
after compresssion. This was for anaglyph pics, so the color shift
was important in some of the detail from the pics I was trying to
compress.

I then decided to convert them (continuous tone) to GIF. This too
obviously altered the color scheme and wasn't much better. But for
the high contrast images, I decided to go with the GIF since even
though it would change the colors a bit from the original picture,
the high contrast areas would hold up better. This is another 
reason why most clip art is compressed to GIF rather than JPEG
I think.

Also it's not a good idea to convert a GIF to a JPEG IMO because
the colors come out much worse. This might be why some might think
that JPEG is not as good. But an original uncompressed continuous tone
image converted to JPEG, beats GIF hands down.

One suggestion I think would be wise, since I don't see this mentioned
often, is to do all the editing work and save the work as uncompressed
till you are finished with the image. When the image is finished in
subsequent sessions then save it as a JPEG for web or final storage as
a compressed file. This would be especially important I think for lossy
files.

Gabriel



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