Cycles Denoise on Render

Hi Yah,

Not that long using Blender & Cycles, but starting to work my way around them. Wondering if someone can point me in the right direction. I’m doing an outside garden render, single image shot. In the viewport, the scene looks fine, during the final render it looks exactly as I expect until the denoise kicks in and washes the image.

This is a clip of the scene in the viewport:


This is what happens after the Optix denoise does it’s thing:

Maybe I’m missing something, have checked all settings and nothing different to what I usually have. Could be a case of not seeing something obvious, so any pointers would be great.

Thanks in advance

Yikes. I use denoiser in post, so I would try to use that one and mask the image out so it doesn’t denoise it. I don’t think you can use rendering denoisers on regular images.


Unfortunately the way that Optix works is to use AI and does not recognize “good” noise from “bad” in a very reliable way. For high detail scenes you want to de-noise in post/compositing or increasing other settings to compensate. I have been trying to work with volumetric lighting and Optix de-noiser basically ruins the render by getting rid of good noise (fog,mist,atmospheric volumes, etc.)


Optix is mainly useful for quick previews due to how fast it is, you will want to use OIDN for final renders as the quality difference can be significant.

Even then, it might blur some small detail, but it is possible to keep some of that if you use the compositing node on the individual passes instead (as you can opt to not denoise the direct lighting passes if they are converged).

Thanks for all the replies, much appreciated…the previous renders I’ve done in Blender have all been stills, haven’t ventured to animation yet. All of those have had HDRI lighting and the default View Layer Properties have had the Denoise Optrix ticked, the other final renders have come out a treat and no adding in a composite denoise node.

The only thing different here is I’ve used an add-on Physical Atmosphere for the lighting, so I’m just wondering if this is where the problem may be as Peter Steel mentioned that when he has an Atmosphere the denoise ruins the rendered image.

The reason I’m using this and not an HDRI as I have in the past is I’ve noticed that with HDRI’s in this scene there are so many fireflies even after going through the numerous methods listed online and on youtube to reduce them. So I thought I’d use a physically correct sun/lighting solution, I’m re-running the render with the Progressive Refine instead of tiles and the Optrix option unticked and use the Blender denoise to see how that goes ???