A LUT, or Look-Up Table, is a mathematical formula that is used to map one set of colors to another. In the context of image and video processing, a LUT can be used to adjust the colors or tonality of an image or video in a way that is designed to produce a desired visual effect.
LUTs are often used in color grading, which is the process of adjusting the colors and tonality of an image or video to achieve a particular look or mood. They can be used to adjust the overall color balance of an image, to add or remove certain colors, or to shift the colors in a way that creates a specific mood or atmosphere.
LUTs can be applied to images and video using software tools such as Photoshop or video editing software. Many cinema/pro cameras and other video production equipment also have the ability to apply LUTs in-camera or in real-time during playback.