Quantization stepper: drag the number of levels and watch the rounding error and banding

Levels L (bit depth)L = 8 · 3-bit

Actual pixel intensity I100

stored value Q

quantization error I − Q

31.875

step size dI

Smooth ramp, before quantization

Same ramp stored with L = 8 levels

Drag L down to 8 or 4 and the ramp breaks into visible bands. Push it to 256 (true 8-bit) and the step size falls to about 1 unit, which is where the error drops below what your eye can see.