RGB Channel darkening when enabling denoiser

[Alex_M]

After an IPR session, I wanted to check the image with denoiser on and off. So I stopped IPR and started toggling between denoiser on and off. I noticed that the image with denoiser turned on is darker. Please check the screenshots below.

I'm using the latest nightly of Vray 5 from Sept. 11. The only render elements in the scene are MultiMatte and Denoiser (Vray).

I don't really know what triggers this. What I remember doing is I started an IPR session, toggled a few times between denoiser on/off, changed the denoiser setting from "default" to "mild", then "strong", then back to "default". Then I toggled between denoiser on/off a few times more and then I stopped the IPR session. Then I started toggling the denoiser layer again and noticed that when the denoiser layer is on the image is darker.

[yavor.rubenov]

Hello,

Overall it seems like something like the scenario described here https://forums.chaosgroup.com/forum/...19#post1083619

Do you have the denoiser opacity less than 1.0 ?

Best regards,
Yavor

[Alex_M]

Hm.. Good question. This I don't remember exactly. Usually I lower it a bit, so I would hazard a guess that I did have it below 1.0.

[Alex_M]

This issue returned today. I rendered my image with Vray GPU and then I noticed that a part of my image needs corrections. So I did a region render and after it finished, the image outside the region got darker. If I turn off the denoiser layer and then turn it on again, the problem goes away... until I render another region.

[Muhammed_Hamed]

Thanks Alex,

I will take a look

Best,
Muhammed

[Muhammed_Hamed]

Hey Alex_M I hope you are having a great start to your week

We are looking into this now, is this reproduceble in all your scenes?
Is there a chance we take a look at your scene please?
here is my Email, muhammed.hamed@chaos.com

Best,
Muhammed

[Alex_M]

Hi Muhammed_Hamed ,
I rarely use Vray GPU so I can't say if it's persistent in every scene. I'll do some tests in the offending scene and send it to you if I manage to reproduce the issue again.

[Pixelcon]

It happens to me when I render a region. It seems to denoise the rendered region and darken the rest of the image. If you hit 'upate' on the denoiser layer in the VFB it should then denoise the entire image and fix the darkened areas.