32 bits banding in simple masks and gradients

Question

hi this is the issue im dealing with
1) im testing with two computers, a good laptop and a good desktop, both new , powerful, both with NVIDIA graphic cards which i guess are supposed to be good graphic cards
2) im using the latest software, photoshop CS4 and AE CS4
3) im trying all this in 32 bits in both and in the other modes later also
4) i am switching off opengl as for the suggestions i receive, and also im seeing all at full resolution
so given all that written above, now we go to photoshop, create a new file say 1920x1080, take a greyscale gradient with the gradient tool and put it on a new layer,
and there it is, the banding
so either there is something really wrong in my setup, or this is a generic problem
i thought it could be my video hardware, but how could this be, both my control panel settings of both computers are set to highest color depth 32 bits, and both have NVIDIA graphic cards, and both are a year old or the desktop a month old, i mean it cannot get much more recent, certainly its not the best hardware around thats for sure, but really i think it should be enough to display an smooth gradient i would hope
i have known about the technique to use Add Noise for a long time to get rid of banding but i didnt remember that banding would happen so easily in a simple gradient or in a simple mask even at 32 bits, this is what puzzles me, i thought the whole point of 32 bits is that these things like this type of banding wouldnt happen
thank u for any help
by the way ,searching around online i have seen so many threads of people complaining about banding,
is Adobe addressing somewhere what seems to be a generic concern about Banding, maybe with a nice article explaining the reasons, causes, and solutions for banding that u may still get in 32 bits etc? that would be very nice
thank u very much again for any advice you could give me, thank you
jav

Answer 1

Banding  is a complex topic and is not going to be resolved here.  Something you wrote  should  to be clarified, however. You mentioned  using 32  bits five times, though I think you were referring to two different measures of bit depth.   I am assuming you meant that you were doing your tests in Photoshop's 32  bits/channel image mode.  You then went on to talk about your Nvidia video setup  stating that it was also 32-bit.  That's fine, but the latter represents 32 bits per pixel, not per channel, and that translates to 8 bits per channel.   One significant reason you cannot set your graphics card  for higher per channel  bit depth is that only experimental displays can handle  more than 8 bits per channel.  In fact, some  LCD displays cannot even produce 8 bits worth of resolution even though they are so specified - they use spatial dither to up the color measure.
The point is that your stated premise that using 32 bits should eliminate banding may be true, but your implementation to verify it is ineffective  as you have only 8 bits per channel on the output or dispay end.   How obvious banding is depends on too many parameters to discuss in this forum, but a significant one is the quality and the calibration of your monitor as well as its contrast settings. One needs to have a correct and smooth monitor gamma set and matched color channel to color channel.   In black and white smooth gradients what sometimes shows as banding, is the color channels being off by 1 color value (or more), that is, the R, G and B values are not equal . Looking at the info panel as you scan across a gradient will show you if this is the case.  This is common in inexpensive monitors.
Changing the smoothness setting in Photoshop's Gradient editor can also change the appearance of banding.  Relevant to this forum, my experience is that looking at smooth gradients in the 32 bit/channel mode produces no banding on my display. So I will assume Adobe has done the coding correctly.   It is the software + the video processing and display adapter + the display hardware and settings + the visual perception of the viewer that all contribute to the perception of banding or contouring.  Kind of a long non answer, but I think relevant to the topic.
Paulo