Here is a short article that shows an 8 bit color cube -> http://en.wikipedia.org/wiki/RGB_color_model#The_24-bit_RGB_representation
I don't see banding but I don't have any issue such as a "crush" to black or other calibration errors. There can be an issue with firmware but let's let Samsung do their service call.
http://forum.blu-ray.com/showpost.php?s=a71773eff8338fe23455bae8c6735af3&p=772933&postcount=46 notes your PS3 may need a slight change.
I've had the LNT4061F LCD for about 6 months now, and ever since I got it there has been very noticeable color banding on color gradients (ie: blue skies, gray gradients such as those on the PS3 menus, dark scenes in video games, etc.). This has been very prominent on both my PS3 (connected with HDMI) and my D-Link DSM520 media receiver (connected with component video). To test I made a blue to black gradient in photoshop and displayed it on both units, and both are horrible. I would have returned the TV, but I didn't notice the issue until I hooked up my PS3 and that was after the return period.
I contacted Samsung support, and they recommended I get the TV serviced. However, I had read that this panel is 8-bit, as opposed to the LNT4065 which is 10-bit. Does this mean that the color banding is just a side effect of the lower color processing? Or is there something wrong with my particular panel? Any help would be appreciated! I don't want to get this thing serviced for a problem that may be inherent to the model in the first place.
Here are some pictures I took of the issue...