Build-in tonemapping is designed to use with standart 3ds Max gamma 2.2. It is reommended to use default gamma settings:
exposure is a general image brightness multiplier.
saturation adjusts the amount of color saturation of the render.
burn value sets over-bright areas contrast. Low values gives soft over-brights and reduces contrast. High values gives hard over-brights and increases contrast.
contrast set image contrast in dark areas.
image blur can be useful to avoid anti aliasing issues on bright edges.
image sharp gives extra image sharpness.
vignetting reduces image's brightness at the periphery compared to the image center.
LUT allows to use look up table from a file to simulate different film/camera responses. It is possible to use an external LUT file or build-in library. The library is modifiable. It scans a LUT folder in 3ds max root folder for a LUT files. User can add and remove LUT files in the LUT folder.
LUT on enables/disables LUT.
LUT strength sets LUT power.