[Tig] jpg vs tiff, (OT), Glenn Chan
rob at colorist.org
Wed Mar 12 13:15:16 GMT 2008
So I've been comparing The Gimp's 8-bit capability with that of
Cinepaint's 16+ bit. (Photoshop also has 16 bit capability but I
leave it out for now as I'm not working with it.)
A NEF (Nikon RAW) image opened in The Gimp shows a certain amount of
fine detail. The same image opened in Cinepaint shows a lot more
detail, in that a textured suitcase on the other side of the room in
the shot has all of its texture visible in Cinepaint and none in The
Gimp. So I would guess, that bit depth in RGB (and I think the NEF
file is 12 bits) contributes significantly to luminance detail.
Forgive what might be a basic question, but I've not gotten into color
bit-depth as applies to Mac/PC paint programs before.
Reading an article at http://photo.net/learn/raw/ , there is
substantial reference given that for print work, 8 bits are enough.
I have read elsewhere this is not true, rather that 8 bits are fine
for Web, but 16 bit TIFFs are de rigeur for printing. And to think
of the math: 12 bit TIFF = 4096 intensity levels for each pixel. 8-
bit (such as JPEG) = 256 intensity levels for each pixel. And here is
the quote from the the URL above that I'm curious about:
"Actually 256 levels is enough, and all printing is done at the 8 bit
level, so you might ask what the point is of having 12 bit data."
(article goes on with a good explanation of why 'upsampling' is almost
always a good idea.)
Now I'd like to ask Glenn Chan, who has been working on plug-ins for
Photoshop, if he would be interested in doing some open source work on
plugins for Cinepaint, which is missing several that The Gimp
offers. The rewards will be numerous but not financial necessarily :~]
rob at colorist.org http://www.colorist.org/robhome.html
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