|Original HDR screenshot (contrast increased in image to illustrate banding)
|HDR with dithering (contrast increased in image)
|HDR with dithering (original contrast)
@renderwonk (Natty Hoffman) told me on twitter:
Pixar dither when quantizing. See "Mastering" section of "Color Pipelines..." course here instead of adding 0.5 and truncating to quantize, they add rand(0,1) and truncateSo I just tried using random noise instead of dithering, and it looks better, although obviously more noisy. (No screenshot I'm afraid) When the noise changes over time it visually blends together. It makes the color transitions much smoother and all kinds of faint details, that where simply a single color before, end up being more visible.
Unlike Pixar I made the noise scale somewhat with the amount of light, this made the noise a bit more visible (especially on a monitor with a very high contrast & brightness, but not too much) but it also smoothed out the more brighter transitions. Interestingly enough the noise looks similar to the noise that you would see when you're in a poorly lit environment. Although the noise/dithering won't scale the extend of the contrast of your display device, it does extend the perceived color precision.