Special effects make-up, prosthetic makeup or FX prosthesis are the tricks that make-up artists use to create the illusion of advanced cosmetic effects. These techniques involve sculpting, molding and casting, helping actors look like monsters, zombies, with advanced skin plagues or scars or even aliens. John Chambers, the makeup artist responsible for movies like Planet of the Apes, The Island or Dr. Moreau or such TV shows as Star Trek, improved and made this technique into what it is today.
A few steps are required before the prosthetic. The process starts with taking a mold of the desired body part, either if it is the face, the hand or the leg, so that the make-up artist can create a base that will fit perfectly to the anatomy of the actor that will impersonate the character. These molds are made from silicone rubber, which are safe to use on the skin, or from prosthetic alginate. The alginate mold is inferior in quality, compared to the silicone rubber. This requires a second layer of plaster or fibreglass bandages, which will add support.
This is the process for creating the negative mold, subsequently filled with gypsum cement, usually Ultracan 30, to create the positive mold. The desired form of the design is thereafter sculpted on top of the positive mold, which will be applied on the face, hand, feet or any other body part of the actor. The edges of the mold are very thin, in order to create a seamless blend with the body part that it is applied onto.
The last part of the process states in taking two more mold parts. The final prosthetic, made of silicone, latex or gelatine is made from the negative. This part is applied on the face of the actor for the role. Its edges are blended seamless with make-up, and painted in the desired colors to create wounds, a natural skin tone or a fantastic look.