Apply a .cube color grade
Load a photo, choose a 3D .cube LUT, and set how much of the mapped result replaces the source color. The export keeps the image dimensions and source format.
A LUT is a table, not a collection of exposure sliders. Every input RGB coordinate points to an output RGB coordinate, which lets one file carry linked changes to hue, saturation, contrast, and channel response.
The 3D color grid
LUT_3D_SIZE 33 describes a cube with 33 × 33 × 33, or 35,937, stored color samples. The first red index changes fastest in the .cube table, followed by green and then blue. DOMAIN_MIN and DOMAIN_MAX define which input range maps to the first and last sample on each axis.
Most image pixels fall between grid points. Tetrahedral interpolation identifies the containing cube, selects one of its six tetrahedra, and blends the four vertices around the input color. This produces continuous transitions without expanding the LUT to every possible 8-bit RGB value.
Input color space matters
A LUT only gives the expected grade when the source uses the color encoding the LUT was built for. A creative LUT authored for an sRGB or Rec.709 image can work on an ordinary exported photo. A technical conversion LUT made for LogC, S-Log3, V-Log, ACES, or another camera pipeline expects that encoded input first.
If the result is clipped, inverted, or heavily tinted at 100%, check the LUT documentation rather than treating intensity as a color-space conversion. Lowering intensity blends away the symptom but does not supply the missing input transform.
Grade strength
Use 100% when checking the LUT itself. For a creative grade, reduce the amount until neutral surfaces and skin stop drifting farther than the job allows. A LUT can alter contrast as well as color, so compare shadow detail and highlights, not only hue.
For a set of related images, apply the same LUT and intensity to each source after exposure and white balance have been brought into line. The LUT then starts from comparable pixels instead of compensating differently exposed files by accident.