J-CLUT is a free, open-source, Java based hald to LUT converter.
LUT means Look-Up-Table. There are a few types of LUT files (1D, 3D) but they all just store rgb values in the form of a table. Those values can then be accessed to grade footage in editing software. In all cases of LUT use, the LUT is the means to make up the difference between source and result.
Basic How To:
1.) Download a hald image from the Internet. 2.) Apply any color-correction on the image. 3.) Save the resulting image as a .png file. 4.) Use the previously saved image with this library. 5.) You now have a LUT (Look Up Table) with those exact corrections.