Huck-
Good. Now for the rest of the story. Up until about 2 years ago, any digital processing (visual effects composites, mostly) were done in 8 bit color space. Up until about 4 years ago, 2k resolution was standard for output to the film recorders. When the idea of a higher rez was seriously considered (made possible by cheaper data storage, affordable higher rez film recorders and finer grain film stocks developed for, among other things, digital film recording), the standard became 3k and soon after, 4k. The increased output resolution gave rise to development of higher bit depth renders, currently 16 bit using Maya, Shake and Inferno software. Still, most matte paintings are done in 8 bit color due to the limitation of Photoshop, and are incorporated into 16 bit composites. Some elements are painted in Matador, which renders in 16 bit color, but it's not very user friendly and hasn't been updated in years.
So, we're talking about resolutions that are FAR beyond what current home theater projectors can handle, with these decisions made for archival, original negative output. 4k is fine for 70mm, and we go up to 6k or 8k for Imax and Omnimax.
Now let's get down to it.
http://www.avsforum.com/ubb/smile.gif For our purposes, namely scaling DVD movies to the hardware resolution of our projectors, is an 8 bit video card enough? Will a higher color bit depth make a difference? I risk contradicting myself by exclaiming YES YES YES YES YES!!!!!!
8 bits are MORE than enough, IF they are the RIGHT BITS. What this means is that after the image is digitally mastered, if it is kept in its original form (no upscaling, rotation, skewing, etc.), 8 bits will provide more than enough color information. Hoewever, if the pixels are altered in any way, even a .001 differentiation, EVERY pixel needs to be recalculated and will suffer degradation. Banding occurs when pixels are stretched (scaling) and it is there that 8 bit depth becomes deficiant. If I have a low rez image and I want to alter it, I will usually scale it up to a much larger size than my target size, do my alteration, then scale it down to the final size. This will almost always give me a more refined result than if I processed the image at the same rez. More info, better scaling. The scaling is the key. The higher the color bit depth, the greater the palette to work with when adding information that wasn't there before. If your projector's hardware resolution was exactly the same pixel height and width as the MPEG 2 image file on the DVD, 8 bits would be optimal.
Add on top of this that digital color space is linear color space. Using non-floating point calculations, this puts middle gray at about 18 on a scale from 1-100. You can just a imagine what linear scaling will do to a linear grayscale.
So, after the scaling or filtering, do 10 bits, 12 bits, 16 bits matter? Only if the pixel amount or position needs to be recalculated once again. Otherwise, a higher bit depth buys you nothing.
Every day I work with an incredibly detailed, subtley colored image on my 24 bit (8 bit color space) monitor using Photoshop @ 1280x1024 rez. In my case, 8 is enough. In your case however, the video card bit depth is significant.
[This message has been edited by BarkingArt (edited 03-07-2001).]
