GamutMapping

GamutMapping is a Fusion 2D Color node that handles tone and gamut mapping. The Resolve 21 manual documents the primary image Input, an optional Effect Mask and an image Output. It is distinct from the Gamut conversion node, the hard-clipping GamutLimiter and a complete source-to-output Color Space Transform.

Begin by recording what RGB encoding actually reaches the node. The Gamma selector describes the incoming transfer, whereas this panel has no dedicated Input/Output Color Space fields. Setting a final export label to Rec.709 does not establish that the earlier compositing chain has created correct Rec.709 pixels.

Tone Mapping Method is specifically a luminance/dynamic-range choice. None disables this mapping, Clip discards out-of-range values, Simple uses a basic curve, Luminance Mapping favors consistently standardized inputs, DaVinci provides smooth controlled roll-off, and Saturation Preserving retains more chroma at the extremes.

The manual describes Simple as mapping roughly 5500 nits into 100 nits, so extremely bright detail can still clip. DaVinci applies controlled extreme desaturation; Saturation Preserving provides additional conditional highlight saturation roll-off. No method automatically guarantees lossless HDR-to-SDR rendering or colorimetric accuracy.

Max. Input and Max. Output Luminance set the tone-mapping peak context. Avg. Input Luminance adjusts visual adaptation between bright and dim viewing conditions rather than reporting a sampled average pixel value. Derive these values from signal/mastering requirements and inspect scopes before rendering.

Gamut Mapping Method handles saturation independently: None leaves chroma unchanged, Saturation Compression remaps extreme saturation more smoothly, and Clip hard-clips it. This Inspector does not establish destination primaries. A separate Gamut/CST stage or managed pipeline must perform the actual gamut and transfer transform.

Archived Resolve 21 screenshots show the name Saturation Compression; chapter 93 refers to an analogous Saturation Mapping method with conditional Saturation Knee/Max. Its conditional Sat. Rolloff Start/Limit are also documented for Saturation Preserving. These controls are not expanded in the original screenshots, so the guide does not invent their on-screen appearance.

Apply Forward OOTF performs a scene-to-display domain adjustment; Apply Inverse OOTF performs display-to-scene adjustment. These should be attached to a deliberate color-management design, not switched on as creative looks. RCM/ACES output management or a neighboring CST may already own the domain conversion.

The documented optional blue Effect Mask socket is applied after the node computes its result. Mask streams cannot replace the orange primary image Input. A masked tone/gamut operation is valuable for diagnostics, but may leave a spatial mixture of display behaviors that is inappropriate for a uniformly encoded final master.

Pre-Divide / Post-Multiply is relevant to premultiplied RGBA data: nonlinear changes to RGB already multiplied by alpha can contaminate edges of titles, glows or CGI. Determine whether the actual source is premultiplied or straight-alpha and inspect a rendered edge over dark and light backgrounds.

A reliable workflow records the incoming transfer and gamut, the owner of color-space conversion, mapping strengths and peaks, and the scene/display domain before anything is exported. Compare None versus mapping branches with consistent scopes and actual final output files.

The typed practice graphs check cable direction and image/mask separation only. They do not numerically validate nits, gamut compliance, HDR-to-SDR appearance or RGBA edges. Those outputs remain pending a native Resolve 21 test.