LUTs, or Look-up Tables, are a tool used in the pre-production, production, and post-production process, although they are most commonly associated with post-production. They are essentially mathematical formulas that map one set of colors to another, and they can be used to correct the color and exposure of footage or to create a creative look that matches a specific vision or genre. LUTs can be used in a variety of ways, including adding an aesthetic look to an image, converting footage from one color space to another, or even to calibrate monitors on set.

In the context of color grading, a LUT transforms color input values (camera) to desired output values (final footage) . They are preset files that apply a specific color grading to video clips, giving them a certain mood, style, or aesthetic. LUTs can be directly applied to footage, and they are the quickest way to grade footage once it has been color corrected.

There are different types of LUTs, including technical LUTs, creative LUTs, 1D LUTs, and 3D LUTs. Technical LUTs are used to correct the color and exposure of footage, while creative LUTs are used to create a specific look, feel, or aesthetic to an image. 1D LUTs and 3D LUTs are used to adjust hue, saturation, luminosity, gamma, and contrast separately and can change as conditions in the image change.

LUTs are non-destructive, so they can be loaded and deleted at will. They can be specifically engineered for different types of footage, such as LOG, RAW, Rec.709, Rec.2020, HDR, and more. LUTs can be downloaded from camera manufacturers, software companies, and independent producers, and they are often designed for specific purposes, such as color correcting footage shot by their cameras or for emulating the distinctive looks seen in movies and TV shows.

In summary, LUTs are a tool used in color grading to transform color input values to desired output values. They can be used to correct the color and exposure of footage or to create a specific look, feel, or aesthetic to an image. There are different types of LUTs, and they can be specifically engineered for different types of footage. LUTs are non-destructive and can be downloaded from various sources.