WHAT IS A LUT?
A LUT (Look Up Table) is a mathematical formula that transforms the color of a source image to new parameters in the resulting image. LUTs can be technical, such as transforming one colorspace to another or for calibrating a monitor, or they can be creative, such as giving your video a specific look or emulating a certain film stock.
Since LUTs apply the same color transformation regardless of the source footage, it is important to note that a LUT is not a one-click-and-you're-done solution. If the source shots do not match each other before the LUT, they will still not match after you apply the LUT.
Since many programs support LUTs, they are a powerful and universal color correction tool. They will help you save time with your creative color grading and make it easy to achieve a professional look.