I have made live my beta version of my color lithophane tool at ptpcreate.com. At launch it has color profiles for Epax 3d, Printed Solid, and Bambu Labs CMYK filaments.
The tool is limited for now because I need to better understand server load, this is my first time using cloud computing. The limitations mean there are only 2 nozzle size choices (0.2 and 0.4) and the output is fixed at 108x144, which is the size of the Bambu Labs lithophane holder.
There are definite quality improvements over what I first developed in 2019. Blacks are not nearly as blue as they were before (though still some).
While better, skin tones definitely need more work. I may have to go to 5 colors to completely fix it.
Check it out and let me know what you think!