LUTCubeApply

The node receives two different image streams. The main one contains the picture to transform; the reference contains ordered color samples. A colorful cube may look like artwork, but its pixels describe a mapping table rather than an ordinary composite layer.

A neutral Creator connected directly to Reference Image defines an identity transform. This is the first check of wiring and input handling: compare the source and Apply within the precision being evaluated. Only then place static color tools between Creator and Apply.

Controls has no dedicated creative sliders. The source PNG shows the active Settings tab: Blend, Process R/G/B/A, mask options, layer selection, GPU, comments and scripts. Empty Controls does not mean Apply has no settings; it means the look arrives through the green input.

Effect Mask limits application after the effect is processed. To desaturate part of a shot, create a globally desaturating cube image and connect Rectangle or Polygon to Apply’s blue input. Do not paint that coordinate mask onto the cube itself: its location would become tied to the color-sample layout.

The shared image type does not guarantee matching color interpretation. The cube and picture must use the intended input values. Resizing, automatic conversion on loading and display LUTs can obscure a comparison; track cube dimensions and viewing settings separately.

An RGB table does not define a universal transparency transform. Use an opaque source for the first test, then separately inspect Process A, semitransparent edges and mask settings. Preserve 32-bit float and sample layout when exchanging the cube through an external file. To write a conventional 3D LUT from the cube, use Analyzer on a separate branch.