ACESTransform

ACESTransform [ATr] is a Fusion Color node that processes a normal 2D image stream. It exposes a required Input, an optional Effect Mask, and one normal image Output.

The most important discipline is to stop treating Input Transform and Output Transform as creative presets. They describe the signal state before and after the node, so they should be chosen from the real source and delivery pipeline.

ACES Version selects the ACES generation used by the transform. The captured Resolve 21 Inspector shows ACES 2.0, 1.3, 1.2, 1.1 and 1.0.3.

ACES Version is not a look control. In production it should follow project requirements, transform/AMF compatibility and the wider interchange pipeline rather than whichever option happens to look nicer in the Viewer.

Input Transform tells the node how to interpret the incoming signal. The captured menu shows No Input Transform, several Blackmagic Design Film/4K/4.6K and Gen 3 options, Fujifilm F-Log/F-Log2/F-Log2 C, Insta360 I-Log, and inverse Rec.709/sRGB options.

No Input Transform means that this node does not perform an input transform. It is not automatic color-space detection and does not prove that the incoming image is already in the intended ACES working state.

Choose Input Transform from the actual camera/log/display encoding. If an upstream step has already converted the source, applying the same input-side interpretation again creates a double transform and corrupts the grading baseline.

Output Transform defines the intended viewing or delivery rendering. The captured Resolve 21 menu includes Rec.709 BT.1886, sRGB, Display P3, P3-D65, multiple P3-D65 ST2084 targets, Rec.2100 HLG and other display contexts.

No Output Transform disables the output transform inside ACESTransform. That is only appropriate when a downstream stage intentionally expects a scene-referred/working signal and performs the display transform later.

Do not choose Output Transform solely from the current monitor appearance. It should match the real mastering path; otherwise the Viewer may look plausible while export or downstream color management is technically wrong.

If project color management, another ACESTransform, CST, OCIO or a later display pipeline already performs the target transform, adding another Output Transform here creates a double transform. Write down the signal state before and after this node.

Gamut Compress Type exposes None, ACES reference gamut compress and ACES parametric gamut compress in the captured UI. This is a dedicated high-chroma/out-of-gamut handling stage, not a general Saturation control.

ACES Reference Gamut Compression is intended for difficult colors that sit outside a useful working/display gamut, including highly saturated sources such as LEDs, neon and tail lights.

Do not apply gamut compression repeatedly without intent. Repeated compression in different parts of the pipeline can further squeeze high-chroma regions and make diagnosis harder.

Pre-Divide / Post-Multiply addresses premultiplied alpha. With it enabled, RGB is divided by alpha before color processing and multiplied by alpha again afterward.

On opaque footage this checkbox is rarely the main variable. On keyed, CG, PNG, Text+ or other semi-transparent graphics it is important for keeping soft edges clean through strong color transforms.

Effect Mask is the separate blue mask input. It does not describe color space, replace the Input, or provide a reference image; it only limits spatial contribution of the processed result.

Local masking deserves special caution in color management because transformed and untransformed regions can end up in different signal states inside one output image. That mixture should be deliberate rather than accidental.

The most reliable Inspector reading order is Version → Input Transform → Output Transform → Gamut Compress → premultiplied-alpha handling. That order exposes source-state mistakes and double transforms quickly.

The Settings tab contains common Fusion controls, but the architectural boundary does not change: ACESTransform remains a 2D image processor rather than a project-level color-management switch.