What is Highlight Compression?

Please do not confuse Highlight Compression with Highlight Clamping 

You can find Highlight compression parameters in:

• 3ds Max:
  • Render Setup > Camera > Edit Tone Mapping > Highlight Compression
    
     
  • The Tone Mapping rollout in a Corona Camera
    
    
    
    
• Cinema 4D:
  • Render Settings > Corona > Camera/Postprocessing
  • Corona Camera tab > Tag Properties in a Corona Camera
  • Corona Postprocess dialog opened from the Picture Viewer
    
    
• Both 3ds Max and Cinema 4D:
  • Post tab in the Corona VFB:
    
    
    

Increasing it reduces the effect of burning in brightest parts of your image - this is useful for example if you want objects behind the window to be visible on a sunny day. There is no "correct value" for highlight compression as it has purely artistic value. Usually, there is no need to increase it above 2-5 but in some cases, you may even want to increase it to very high values like 50 or more.

Note: always use highlight compression value of 1 when you are saving render elements for later composing or saving 32-bit files for post-production.

Examples

Highlight compression = 1 (default value)

There are very bright areas caused by direct light and refractions.

Highlight compression = 2

More detail is recovered from brightest areas.

Highlight compression = 3

Brightest areas are becoming "flat".

Highlight compression = 100

The image lacks contrast as bright areas are becoming less pronounced.

Highlight compression = 0,5

There is a lot of burning in brightest areas of the image.