Aerial Perspective Color Banding

[Daniel_Ray]

I am getting color banding in my scene with aerial perspective. It might be too "smooth" which is causing issues. Here is an example of what I mean. Anyway to solve this?

[vladimir.nedev]

It's the same thing as color banding in a photograph, there are a lot of tutorials covering how to remove it.

This happens because an 8-bit monitor has only 256 different levels of brightness.
When you have a dark smooth gradient like this, you are basically seeing 2 neighboring brightness levels on your monitor each covering a very large area, so the border between them becomes very obvious.
In order to remove it, you add a very slight noise in post on the whole image, which randomly shifts the pixels one brightness level up or down.
This is called dithering.

Maybe in the future we can add this effect to the VFB. Also I don't think we support 10-bit monitors at the moment in the VFB, but a 10-bit monitor maybe solves this issue too.

Greetings,
Vladimir Nedev

[Daniel_Ray]

It's the same thing as color banding in a photograph, there are a lot of tutorials covering how to remove it.

This happens because an 8-bit monitor has only 256 different levels of brightness.
When you have a dark smooth gradient like this, you are basically seeing 2 neighboring brightness levels on your monitor each covering a very large area, so the border between them becomes very obvious.
In order to remove it, you add a very slight noise in post on the whole image, which randomly shifts the pixels one brightness level up or down.
This is called dithering.

Maybe in the future we can add this effect to the VFB. Also I don't think we support 10-bit monitors at the moment in the VFB, but a 10-bit monitor maybe solves this issue too.

Greetings,
Vladimir Nedev

Ah silly me. Thought it was something worse than that for some reason. Problem solved thank you!.

But i'm curious. Is there any way to "dither" in vray? I was just using photoshop to add noise. The main problem was that aerial perspective renders really smooth. How could I get more noise in a scene with and without aerial perspective? Should I increase the threshold for Image Sampling?

Sorry for the questions, I was using Octane Render before and Octane is extremely noisy in dark scenes so that was never an issue.


Edit:

Nevermind I'll just keep doing it this way. Thanks again for the help.

[vladimir.nedev]

But i'm curious. Is there any way to "dither" in vray?

Not possible at the moment as far as I know.

The main problem was that aerial perspective renders really smooth. How could I get more noise in a scene with and without aerial perspective? Should I increase the threshold for Image Sampling?

That's the nice thing about aerial perspective compared to environment fog, it renders with no noise.
It's better to fix the banding in post than to try to introduce noise in your render, I think.

Greetings,
Vladimir Nedev

[^Lele^]

Yeah, dithering for display would make noise evaluation impossible in renders, it's not something we should be doing ourselves (at least by default).
As long as you save a FP image, as Vlado said you'll be able to do whatever post work you'll require on continuous (as opposed to stepped) data, so to best fit your output device (Film, 8/10 bit monitor, HDR TV Display, Print, you name it.).

[Daniel_Ray]

Yeah aerial perspective is extremely efficient. I'm really liking how fast it renders. I was just surprised at how smooth the atmosphere was.

I meant a dithering feature in aerial perspective. Its not really an issue because of all the work arrounds.

I just have to make sure I save the file as 16 bit or higher then convert to 8 bit or add noise with a brush or filter. Converting 16 to 8 bit surprisingly makes the banding disappear.

If I save as 8 bit right away, the banding stays even with the noise.

Appreciate all the help.

[vladimir.nedev]

Converting 16 to 8 bit surprisingly makes the banding disappear.

What software do you use to save from 16-bit to 8-bit ? Maybe it applies dithering automatically when saving from 16-bit to 8-bit.

Greetings,
Vladimir Nedev