ColorSpaceTransform

**CST is not a LUT.** Color Space Transform [CST] converts primaries/gamut and transfer encoding mathematically using the Resolve Color Management engine. It does not discover the source format from image appearance.

**Signal-state contract.** Before every CST identify Input Color Space and Input Gamma; Output Color Space and Output Gamma then declare what the downstream nodes receive.

**Three different operations.** Gamut transforms handle color primaries, gamma handles transfer encoding, and Tone Mapping handles large dynamic-range differences. Substituting one menu for another does not solve the same problem.

**Original Inspector.** Seven retained screenshots show four color-state dropdowns, Swap, Tone Mapping, paired Custom Max controls, Adaptation, Gamut Mapping, three Advanced toggles and Pre-Divide/Post-Multiply.

**Source identification.** Canon Cinema Gamut / Canon Log 3 is correct only for footage actually recorded in that mode. Camera primaries and transfer curve must match provenance rather than a pleasing Viewer look.

**Working space.** With explicit node-based management, an input CST can normalize camera Log into DaVinci Wide Gamut / DaVinci Intermediate before compositing and creative operations, without prematurely rendering to Rec.709.

**Separate output.** After creative processing, a second CST can render to Rec.709 / Gamma 2.4 for a matching SDR delivery. Its Input fields must describe the actual state delivered by the upstream working chain.

**None before DaVinci.** For a technical input-to-working transform, start without tone/gamut compression if appropriate. Choose output-stage rendering based on the source, intended display and required QC rather than habit.

**Six tonal methods.** None avoids explicit mapping, Clip hard limits, Simple approximates range mapping, Luminance Mapping and DaVinci implement controlled compression, while Saturation Preserving retains more highlight chroma.

**Two adaptation ideas.** Adaptation inside Tone Mapping is about HDR/SDR viewing adaptation; Use White Point Adaptation performs chromatic adaptation between reference whites such as D60 and D65.

**Nits are not gamma correction.** Custom Max. Input/Output specify reference peaks when enabled; they do not detect mastering metadata or repair wrong gamma. Both corresponding checkboxes are off in the saved Inspector.

**Gamut mapping is separate from tonal rendering.** The captured menu shows None, Saturation Compression and Clip. The manual also documents conditional Saturation Knee / Max controls, but the screenshot does not prove their current values.

**Forward and inverse OOTF.** These toggles bridge scene-referred and display-referred states. Do not enable them blindly when project-level management already owns the same operation, or the image may be rendered twice.

**ACES caveat.** Even if ACES spaces are listed, the Resolve manual explicitly says CST colorimetric transforms do not replace Academy IDT/ODT. Use ACES Transform for a real Academy pipeline.

**RGBA and masks.** Input carries an image, while Effect Mask limits the processed region. Pre-Divide/Post-Multiply helps protect premultiplied composites; exact alpha and feather behavior still requires live verification.

**Why Swap cannot reverse everything.** You can compare the numerical A↔B transform, but hard clipping, tone mapping and gamut compression may not be invertible. Do not claim bit-exact reversibility without controlled measurements.

**Examples are not one-size presets.** The four authored Flow graphs demonstrate signal management; actual source metadata, live host behavior and viewing conditions must be verified before production use.

**Verification boundary.** Inspector screenshots are genuine archived material and lesson graphs are type-checked statically. A full Next.js build, browser QA, .comp import and native Resolve 21 pixel tests are separate qualification gates.