GamutLimiter

Fusion GamutLimiter is a technical gamut-boundary enforcement tool, not a general-purpose grading node. A typical use is Rec.2020 delivery where QC allows saturation only inside a smaller target such as P3. Unlike soft gamut mapping, the limiter hard-clips colors that fall beyond the specified boundary.

The key correction from the older article is loss of information: hard clipping does not guarantee preservation of differences among highly saturated source colors. The Resolve 21 manual is explicit about this. Two distinct neon colors beyond the allowed boundary may collapse to similar values. Saturation adjustments downstream cannot reconstruct clipped differences.

Current Gamut declares the actual RGB primaries reaching this exact node. The values may no longer reflect the original camera profile if previous CST, Gamut, LUT, DCTL, OCIO or project color management has already transformed the image. A camera brand is not enough to determine the signal at the insertion point.

Current Gamma specifies the input transfer curve. Archived dropdown screenshots show Linear, several log encodings and Gamma 2.x options. Treat Current Gamut and Current Gamma as a pair: interpreting log-encoded values as Linear changes how the limiter decides which colors exceed the selected boundary.

Limit Gamut is different from both current-state declarations: it defines the permitted destination boundary. Rec.709 may be right for some SDR masters, but the required target could instead be P3-D65, P3-DCI or a wider gamut. White-point variants are not interchangeable and should be selected from the delivery specification.

The manual provides a concrete case: output remains in a Rec.2020 delivery container, while a P3 constraint caps the allowed saturation. Applying the P3 gamut limit does not by itself convert or retag the final file; the output color-management transform and metadata must still be handled correctly.

Avoid placing GamutLimiter too early. A defensible flow is: document the incoming encoding, normalize when necessary, build the creative look, apply perceptual gamut mapping if color relationships must be preserved, then apply a late limiter and measure the delivered output. Effects added after the limiter may introduce new out-of-gamut pixels.

This node is not an HDR-to-SDR tone mapper. Its displayed Inspector does not contain tone-mapping methods or a highlight roll-off curve. It is not a LUT or an ACES ODT. If retaining detail in saturated regions is essential, perform controlled gamut mapping or an appropriate Color Space Transform before the final limiter.

Resolve 21 documents exactly two Gamut Limiter inputs: a required orange 2D image Input and an optional blue Effect Mask. The mask limits the processed adjustment spatially. In a whole-frame QC use case, a localized mask may leave unmasked pixels outside the target gamut, so avoid equating masked diagnostics with master compliance.

The archived Controls screenshot includes a Pre-Divide / Post-Multiply checkbox. On premultiplied CG or soft Text+ alpha edges, temporary unpremultiplication may protect semitransparent RGB values. Confirm the actual alpha mode and compare edges over light/dark backgrounds rather than assuming every EXR/PNG needs the same checkbox state.

Viewer appearance is not a compliance report. Viewer LUTs, project-level color management and final output encoding may change how pixels are displayed or exported. Inspect image scopes, known color-patch signals and the delivered render. The relevant question is whether the required hard boundary has been enforced without unacceptable lost color differences.

The embedded exercises certify documented connector types and demonstrate editorial sequences; they are not executable .comp files. Native Resolve 21 must still validate post-clipping RGB values, premultiplied-edge behavior and actual QC measurements on rendered material.