A: This is a complicated subject, and the results depend on a lot of variables. If live models are involved, there are also safety issues. Obviously, all I can do here is give you a few pointers, not a complete class on the subject. While I don’t know of any online sources of the information and materials you need, you might try getting in touch with Pink House Studios, 35 Bank Street, St. Albans, Vermont, 802-524-7191, and talk to Mark Prent, the owner. He specializes in life-casting techniques, carries a line of supplies, and also sells instructional materials including video tapes.

Plaster bandage masks can be done quickly, but the results are not great, especially if you are interested in capturing detail. (Don’t tell George Segal I said so.) If you are interested, there are instructions for this process posted at Far-out Fabrics.

Dental alginate is the best negative material I’ve found for this sort of thing; it will capture fine detail, but it isn’t strong. Prent sells a slow-set version which gives a bit more working time. The alginate will sometimes tear when one is unmolding the plaster positive, especially in deep or trapped undercuts. Count on one good positive only per mold. This can of course be remolded with a rubber compound, if multiple casts are required. Casting plaster works as a positive casting material in alginate or rubber molds, as do other gypsum cement products which are stronger.