How can I fix 16 bit PNG output dithering problem?

#1

Hello everyone,

I have a serious problem with 16 bit PNG output, I’m getting dithering problem. I attached a test file. Anybody knows how can I fix this problem?

I normally work with 16 bit PNG. I tried to get 8 bit and I saw that it was correct. I don’t really know when this problem started but I guess it is related to color space thing. I’m using 2023.1. With previous version there was same problem. I couldn’t try older versions.

If I change color space with ACES in project settings it seems that problem is gone but it destroys my all colors and light balance.
and file format does not effects. PSD, TIF, PNG. as long as output is 16 bit there is a dithering problem.

thank you
outbut fles:

correctView_8bit_render_output
correctView_8bit_render_output.jpg1280x720 35 KB
jpg
wrongView_16bit_PNG_render_output.jpg.png1280x720 764 KB

c4d file: DitheringProblem.c4d (330.4 KB)

#2

I can’t try your file because I don’t have C4D installed but when you say you have a dithering problem are you saying the 16 bit version is not being dithered?

How are you viewing the 16 bit version? Can you confirm the posterisation is not being caused by your viewer rather than the data being posterised? Have you viewed the image in the compositor? Do you have a 10 bit monitor?

It has been a long time since I used C4D for rendering and can’t remember a whole lot but I have a very vague recollection that dithering is only for 8 bit formats.

If you are rending multipasses for compositing then you owe it to yourself to dispense with 8 and 16 bit sRGB formats and use OpenEXR in either Half Float or 32 bit Float.

ACES doesn’t screw with your lighting or colours it just requires you to understand colour management, same with OpenEXR linear images. You’ll need to apply a colour space transform to get from ACES to a delivery colour space like sRGB or REC709 etc.