Overview: Fundamentals

Tone-mapping fundamentals explain why source and display ranges differ and what HDR adaptation aims to preserve.

Begin with the source's light range and the output's useful range. An HDR-to-SDR conversion has a different target from adapting one HDR representation to another HDR display. These pages establish the purpose of the transformation before individual curves and processing choices are compared.

• Why tone mapping is needed
  Tone mapping adapts a picture's brightness range to what the output display can reproduce.

• How HDR-to-SDR tone mapping works
  HDR-to-SDR tone mapping compresses the picture's brightness range within a conversion that also handles color and signal encoding.

• HDR-to-HDR tone mapping
  HDR-to-HDR tone mapping adapts HDR pictures to a different HDR brightness range while keeping the output in HDR.