I’m finishing off a scene at the moment, and while tweaking a few render settings noticed something I’d like to discuss with the Intel Open Denoiser, specifically compared to good ol’ rendering with a high sample count. What I noticed was that while all the noise is gone from the image as intended, it almost has a look about it like it is reducing the color depth? See the below images and I’ll discuss a bit more.
Close-up of a cabinet in my scene, 5000 samples:
Same shot, with the denoiser:
You can see slight color banding on the denoised image that isn’t present on the first one. It is more pronounced in the render window before saving. The conclusion I’ve drawn from this is I will probably continue to use just a high sample count for renders for a couple of reasons:
I’m not a fan of the above ‘banding’ look where it looks like the color depth has been reduced
I actually prefer the look of a little bit of noise in my image (not fireflies though). I know many disagree but I’m of the opinion the effects we add on that photographers try to remove - DOF, noise, chromatic aberration etc are good when tastefully present in a render
Render times aren’t a big deal for me, I’m happy to leave it rendering overnight on a 1080ti
Now this doesn’t mean I see no place for the Intel Open denoiser. The quality it can produce for preview renders with next-to-no samples is astounding, and really improves a workflow. You’ll probably notice I have no question at the end, I’m actually just interested in the point of view of more experienced artists.