Blender 2.79 Cycles Renders Depth/Mist with Banding in 32 bit .EXR Files #57747

New Issue

Beau Gerbrands · 2018-11-09T15:39:37+01:00

Beau Gerbrands commented

2018-11-09 15:39:37 +01:00

Windows 10, GTX 1080 ti

Blender 2.79b f4dc9f9d68

Hi guys,

When rendering a depth pass in this case for Nuke, and outputting it to a 32bit .exr file, we are getting banding. Check the .blend example.

Is it possible that there is going to be a fix for this soon? Our compositors noted that 16 bit .exr files should be fine with a depth pass.

Thanks,
Beau

cycles_exr_depth_banding_not_32_bit.blend

Press F12 and see the banding appear, check the values (viewer node) and see the stepped/jumping values.

Windows 10, GTX 1080 ti Blender 2.79b f4dc9f9d68b Hi guys, When rendering a depth pass in this case for Nuke, and outputting it to a 32bit .exr file, we are getting banding. Check the .blend example. Is it possible that there is going to be a fix for this soon? Our compositors noted that 16 bit .exr files should be fine with a depth pass. Thanks, Beau [cycles_exr_depth_banding_not_32_bit.blend](https://archive.blender.org/developer/F5460613/cycles_exr_depth_banding_not_32_bit.blend) Press F12 and see the banding appear, check the values (viewer node) and see the stepped/jumping values.

Beau Gerbrands commented

2018-11-09 15:39:37 +01:00

Added subscriber: @Beaug

Brecht Van Lommel commented

2018-11-09 15:59:18 +01:00

Added subscriber: @brecht

Brecht Van Lommel commented

2018-11-09 15:59:18 +01:00

Are you sure there is banding in the resulting EXR files? Dither in the Post processing panel is set to 0.0 in this file, so when the render is displayed there is banding. But looking at the values in the EXR I couldn't see any banding.

Beau Gerbrands commented

2018-11-09 16:09:37 +01:00

In #57747#552154, @brecht wrote:
Are you sure there is banding in the resulting EXR files? Dither in the Post processing panel is set to 0.0 in this file, so when the render is displayed there is banding. But looking at the values in the EXR I couldn't see any banding.

Hi Brecht,

This is what we see when banding is on a value of 2:

This isn't a monitor issue? Are you using the same Blender version?

Thanks :)

> In #57747#552154, @brecht wrote: > Are you sure there is banding in the resulting EXR files? Dither in the Post processing panel is set to 0.0 in this file, so when the render is displayed there is banding. But looking at the values in the EXR I couldn't see any banding. Hi Brecht, This is what we see when banding is on a value of 2: This isn't a monitor issue? Are you using the same Blender version? Thanks :) ![banding.PNG](https://archive.blender.org/developer/F5461034/banding.PNG)

Brecht Van Lommel commented

2018-11-09 16:15:07 +01:00

One confusing thing is that Blender supports dithering on Render / Viewer node results, but not on loaded EXR images. So those will always show banding, even if the float values are fine.

Did you check the float values when sampling with the mouse, are they really the same within one band? Or is it just a display issue?

One confusing thing is that Blender supports dithering on Render / Viewer node results, but not on loaded EXR images. So those will always show banding, even if the float values are fine. Did you check the float values when sampling with the mouse, are they really the same within one band? Or is it just a display issue?

Beau Gerbrands commented

2018-11-09 16:22:26 +01:00

In #57747#552174, @brecht wrote:
One confusing thing is that Blender supports dithering on Render / Viewer node results, but not on loaded EXR images. So those will always show banding, even if the float values are fine.

Did you check the float values when sampling with the mouse, are they really the same within one band? Or is it just a display issue?

They are not the same, but it is gradual within a band but going to the next one it jumps by a value of 0.002. Quite minor but still a banding issue?

So you are also saying that there will always be banding when viewed in Nuke for instance? Or just a loaded .exr image in Blender? Because both Blender and Nuke display the same banding and amount 0.002.

> In #57747#552174, @brecht wrote: > One confusing thing is that Blender supports dithering on Render / Viewer node results, but not on loaded EXR images. So those will always show banding, even if the float values are fine. > > Did you check the float values when sampling with the mouse, are they really the same within one band? Or is it just a display issue? They are not the same, but it is gradual within a band but going to the next one it jumps by a value of 0.002. Quite minor but still a banding issue? So you are also saying that there will always be banding when viewed in Nuke for instance? Or just a loaded .exr image in Blender? Because both Blender and Nuke display the same banding and amount 0.002.

Brecht Van Lommel commented

2018-11-09 18:08:32 +01:00

When viewing a gradient like this on an 8bit monitor there will always be banding, unless dithering is applied. Nuke has settings for dithering, I don't know if you have that enabled.

I can't say much about that 0.002 value without knowing what the steps are within the band, but it doesn't seem wrong to me.

When viewing a gradient like this on an 8bit monitor there will always be banding, unless dithering is applied. Nuke has settings for dithering, I don't know if you have that enabled. I can't say much about that 0.002 value without knowing what the steps are within the band, but it doesn't seem wrong to me.

Bastien Montagne commented

2018-11-22 12:59:15 +01:00

Added subscriber: @mont29