LUTs are the quickest way to grade your footage once you’ve color corrected. It's important to note that if your footage doesn’t match from shot to shot, is not properly exposed, or is poorly color corrected, that applying a LUT will not work the way you hoped it would.
An even more layman LUT definition is: A preset color look for your video footage. LUTs can be directly applied to your footage. This makes the grading process go by much faster, and specific LUTs can transform footage to look like your favorite films and shows.
1D LUTs vs. 3D LUTs
There are generally two types of LUTs out there that you can use. Both types will use both bit size and bit depth to determine the accuracy of your lookup table.
The bigger these numbers are, the better your color grade can look.