LUT

Abbreviation for Look-up Table, which is a simple tool that is used to apply color transformations. A LUT has a list of inputs and an output mapped to each possible color input. Where a tool like a Hue Shift comprises a simple algorithm that can be applied to each color, LUTs allow for precise control of each color and are often used as presets for color grading. They can also be programmed into any simple processor and can take less processing power than an algorithm.

In its simplest form, the LUT (for 4-bit RGB) is a 16x16x16 matrix (shown below in (8×8)x8x8 form) where the coordinate in the image represents in the input value, and the color at the coordinate represents the output value.