See Sample and Display Filters for more information on RenderMan sample and display filters.
Setting up Display and Sample Filters
Inside your RIS Network, pick a Pxr Display or Sample Filter VOP. Note that you may see the same filter in Display or Sample form. Display Filters work on the pixel level (final results) while Sample filters work on samples before they are filtered to pixels.
Drag the VOP path to the Display Filter or Sample Filter parameter in your render ROP under Filters.
Add multiple display or sample filters to the multiparam to combine filters.