In order to test if LZW compression is truly lossless I did the following:
- I created a master uncompressed TIFF file.
- Created an LZW compressed version of it
- Saved that compressed TIFF back into an uncompressed TIFF.
- Finally compared the latter to the master TIFF with a hex editor.
The files appeared identical, except for one part where a single hex value was increased from 45 to 47 in the post-LZW version of the TIFF. I doubt this has any effect on the quality of the TIFF file, however, can someone explain what causes this to happen?