Bit Depth
8-bit, 16-bit and 32-bit textures
Also known as: 8-bit vs 16-bit texture · 16 bit height map · Texture bit depth · Color depth texture · Banding in textures
Definition
Bit depth is the number of bits used to store each color channel, which sets how many different values it can hold. An 8-bit channel has 256 levels, which is enough for most color textures, while 16-bit has 65,536 levels and avoids visible banding in smooth gradients. Height maps, displacement and some normal maps benefit from 16-bit, because small steps in a smooth surface show as terraces at 8 bits. 32-bit floating-point is used for HDR data.
In production
Export color, roughness and metallic in 8 bits, and height and displacement in 16 bits, unless the engine cannot read them. Painting and filtering in 16 bits keeps quality, and conversion to 8 bits should be the last step. If a smooth surface shows stripes or banding, raise the bit depth or add a little noise. Engines compress textures anyway, so a 16-bit source gives a better result after compression.
