Left: without denoising. Right: with imager_denoiser.

The Arnold Noice denoiser is also available as a post-processing effect. You can automatically denoise images every time you render a scene, edit the denoising settings and see the resulting image directly in the render view. Note that imager_denoiser_noice does not support temporal denoising (required for denoising an animation).

  • The imager_denoiser_noice is recommended for single frame rendering. It does not support denoising an animation sequence and can result in undesired effects between frames. If you want to render an animation, then disable this imager, render the scene with an Arnold EXR driver (Output Arnold Denoiser AOVs enabled), and use the Arnold Denoiser (or Denoising tab in the Arnold render settings, if your plugin supports it).
  • Denoisers won't work as well after imagers have been applied to them. Therefore denoisers should be applied before any other post-processing imagers.
  • You may have to wait a moment before you can see the result of the Arnold Denoiser appear in the render view.

A tutorial that covers how to use the Arnold Denoiser can be found here.


Input points to the previous imager operation in the chain (so that you can stack them and apply multiple operations serially).


Enables the imager.

Layer Selection 

Selects layers processed by this imager with a glob or operator expression. An imager can use a selection to determine what nodes will be selected to be processed by the imager at render time. The selection is an expression that can consist of multiple selections concatenated by: 

  • or (union)
  • and (intersection)
  • not (negation)
  • and not (exclusion)
  • () for nested scoping


Each selection uses glob patterns and regular expressions and a node will be processed by the imager if the expression matches the node name. By default, glob matching is used unless the selection is in a regex quote, i.e. r'<my_regex>'. For example:

specular or diffuse
not r'sss_(direct|indirect)'
r'color_(mask1|mask2)' or r'mask[34]'

Patch Radius

This increases the softness of the denoising (while always preserving the features). The default is 3 (on the big side), but a low value would be maybe 0 or 1, middle 3, and high 5.

For every pixel, the Arnold denoiser will consider its neighborhood patch and look for other pixels with similar neighborhood patches. The radius of this neighborhood can be controlled with the -patchradius (or -pr) command-line argument. The default value is set to 3, which gives a 7x7 square neighborhood.

Search Radius

This is the area over which similar neighborhoods are found. The higher the better, but it will increase the cost of denoising. For every pixel noice will search a square area with a radius set with the command line argument -searchradius (-sr). The bigger this area the bigger the denoising stability and the higher the chance that similar neighborhoods to be considered will be found. The default value is 9, which gives a 19x19 square neighborhood. Setting it to 21 (a search window of 42 x 42) will look over a pixel area equivalent to loading 5 frames.


The strength of the filter is determined by the variance parameter, the higher the variance the more forceful the denoising will be. For variance maybe 0.25 (the default) / 0.5 / 0.75 are good low/min/max values.
How aggressive the Arnold denoiser is in removing noise can be controlled by setting a variance threshold with the command line argument -variance (-v). The default value is 0.25, higher values will make the denoising more aggressive by considering similar neighborhoods that have bigger color disparities.

Output Suffix

When set, creates a new additional output with the input name plus the suffix in which the denoised result will be written into. For example, when denoising the "RGBA" AOV with the output_suffix set to "_denoised", the denoised result will be written into a new "RGBA_denoised" output. It only works with multi-layer drivers.

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