I feel like an idiot right now for not knowing what's causing this. I have been saving out some metal shaders and ran into this problem:

Weird Shadows

If you look at the interior of the ball, the shadows are extremely saturated (almost red). I have nothing fancy going on like SSS or translucency / whatever.

It's even worse at low roughness values:


Do any of you know what's causing this and how to fix?

Thanks much.

  • $\begingroup$ What color is your lamp? This may be a limitation of the fact that computers just use red green and blue, while real life has multiple frequencies that are measured into those three categories with our eyes. $\endgroup$
    – TheLabCat
    Mar 13 '21 at 2:57

Filter Glossy

After doing a little bit of testing, I found that the problem seems to stem from this little booger in the render settings.
little booger

Filter Glossy is designed to reduce noise in reflective caustics by "adaptively blurring glossy shaders," but it seems that one of the side effects is very inaccurate recursive reflections.


  • All 32 samples and denoised with OpenImageDenoise.
  • 12 glossy bounces
  • Glossy BSDF set to Multiscatter GGX
  • Color: RGB (1.0, 0.485, 0.352)
  • Roughness: 0.15

Filter Glossy set to 10.0 (maximum):

Filter Glossy set to 1.0:

Filter Glossy set to 0.1:

Filter Glossy set to 0.0:

  • $\begingroup$ Thanks so much for doing some testing. Even still with filter glossy at 0, there is still quite a dramatic red tint. This doesn't at all look physically realistic. At least I can mitigate the problem, but I'd really like to know how to completely eliminate it. $\endgroup$
    – Jay
    Mar 13 '21 at 15:10
  • $\begingroup$ You can always darken and/or desaturate the material's color or decrease the glossy bounces. $\endgroup$
    Mar 13 '21 at 17:49

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