FileLUT

File LUT [FLU] is a LUT Nodes tool for a 2D image, not a full color-management engine. It receives an image on its main Input, loads a simple 1D or supported 3D table from disk and emits an image after mapping through that table.

The most consequential mistake is supplying the wrong numeric encoding. A camera LUT may expect a specific Log/gamut and target Rec.709 or linear, while a creative LUT may expect an already normalized input. File LUT does not auto-detect the clip encoding or where it sits in a color-managed chain.

Contrary to the old one-input summary, File LUT has TWO Flow inputs: a required orange image Input and an optional blue Effect Mask that limits its contribution. The mask is neither a second LUT file nor a second image composite layer.

Effect Mask is applied after processing the tool. The LUT is evaluated as normal, then the mask limits the effect contribution. A mask cannot replace LUT File or move the Pre/Post-gain stages inside the table.

LUT File stores a path, not the table inside the composition. This keeps compositions small but creates a portability dependency; replacing a shared file on disk may alter every File LUT node referencing the same path.

Format support is specific: the Resolve 21 reference explicitly lists Fusion .LUT and .ALUT, Resolve .CUBE and several other 3D LUT types. A file extension alone does not guarantee that every dialect/dimension parses. Check Console for file-load errors.

Pre-gain adjusts numbers before table sampling and Post-gain afterwards. These are not interchangeable brightness controls around a nonlinear LUT: pre-scaling may change highlight/chroma mapping, while post-scaling changes mapped output and may still clip downstream.

The Inspector Color Space controls the channel representation for the lookup. The bundled dropdown shows RGB, YUV, HLS, YIQ and CMY. RGB is the captured default; it does not automatically imply Rec.709 gamut or gamma.

Pre-Divide / Post-Multiply is designed for premultiplied images: it separates RGB from alpha before color processing and remultiplies afterwards. This matters for feathered graphic, key or rendered CG edges before Merge.Foreground. Straight-alpha input needs independent verification.

File LUT does not automatically normalize camera exposure and is not a substitute for an explicit OCIO Color Space, OCIO File Transform or Color Space Transform pipeline. Document source, working and display encodings plus the LUT position to avoid double transforms.

The two original PNGs confirm LUT File, Browse, neutral gain values of 1.0, Color Space/five visible choices and the alpha checkbox. They do NOT prove actual Flow sockets, parser support for a user-supplied table, unshown Settings controls or rendered pixel accuracy.

Four practice cases isolate the core failure modes: source/LUT compatibility, selective mask, Pre/Post-gain A/B and premultiplied RGBA edges. Typed examples verify cable compatibility, but colorimetric/alpha behavior requires a real LUT and native Resolve validation.