Here is a link to a .pdf handout for Cast Dimensional Prints. Tips and formulas are included, along with materials lists and an extensive bibliography.
Cast_Dimensional_Prints-Michelle_Rozic
Here is a link to a curves adjustment layer to modify image tonal range before outputting to a film negative for photographic carborundum collagraph.
Curve for 100 grit photo carborundum collagraph 20 lpi halftone