My minor at the University of Minnesota was theater, and a special interest to me was stage makeup, and in particular close-up makeup, for small in-the-round stages.

Besides making "scars" with collodion, there was another collodion use: "cotton-collodion buildup". One would use cotton batting (Brit: "cotton wool") impregnated and/or overlaid with collodion to build up parts of the face, such as a protruding chin, prominent cheekbones, and so forth.

Dave Oesterreich