"Banding/ Posterization" is when low color bit depth results in defined “stepping” from one color gradation to another versus a smooth, continuous gradation.
The example below shows the opening of House of Cards with banding present. Note the blue sky.
Banding/ Posterization impacts the Content and Technical Quality of the Asset. Customer experience is negatively affected by low quality images. Banding can be further enhanced on any subsequent deliverables sourced from the asset. The appearance of banding during fades/ dissolves can sometimes be attributed to the refresh rates on some monitors during normal playback. So, it should always be checked in stop/ pause for gradations that are not smooth.
Banding is minor during fades or dissolves.
Banding/ Posterization is significantly noticeable across portions of or the entire image. Banding pattern shifts or fluctuates during playback.
How to Prevent:
Render at least 10-bit. 8-bit visual effects tend to enhance banding/ posterization.
Re-render at least 10-bit and redeliver.