Lookup table may refer to either of the following:
1. In computer programming, a lookup table, also known as a LUT, is an array that holds values which would otherwise need to be calculated. The table may be manually populated when the program is written, or the program may populate the table with values as it calculates them. When the values are needed later, the program can look them up, saving CPU resources.
2. For photo and video editing, a lookup table, or LUT, is a tool used for color grading and correction. It contains specific instructions for automatically applying color changes, such as saturation, contrast, and hue, to certain color values. LUTs can give pictures or videos a consistent look and temperature. They are used to make minor adjustments, replicate an existing style of film, or to make other artistic changes.
Programs that support LUTs include photo editors, like Adobe Photoshop, and video editors, like DaVinci Resolve and Adobe Premiere Pro. You can purchase or download LUTs online, or create them using adjustment layers in Photoshop. They can be stored as .3DL, .CUBE, .CSP, and .ICC files.
If your photo or footage needs to be color corrected (e.g., white balance), an LUT might not immediately fix these issues. If it doesn't look good with an LUT, try making these changes before applying one.