Peak White defines the upper limit of the luminance mapping in your final output. It tells the system how bright the brightest areas of your image should appear on the chosen display medium. This is especially important in a color-managed workflow where your image exists in a wide-gamut, scene-referred space and must be compressed appropriately for display-referred delivery.

• Lowering the Peak White value compresses the dynamic range, pulling down the brightest parts of the picture into a more compressed rolloff.
  
• Raising it allows more headroom, useful for bright displays (like HDR10), but it may expose overly hot areas if your footage wasn’t lit or managed for high-nit outputs.
  
  

This control is essential when managing broadcast-safe outputs or preparing content for different display specs. It also gives a consistent way to avoid clipping or overly harsh highlight rendering when working in a display-referred workflow.