Latex mask generally refers to a full-head enclosure or disguise, often worn by someone as a part of a costume and usually made from natural latex rubber, though some masks can be made of vinyl, silicone rubber or foam latex. Latex masks were among the earlier techniques to be classified as special effects, typically in film but applying also to the theatre,
Latex masks are capable of portraying various guises, including monsters, skulls, mythical creatures, animals, humans, zombies, certain inanimate objects (such as a baseball or a crescent moon) and even political figures (such as Richard Nixon) and popular film, TV or cartoon characters.
Latex masks are generally made in several stages. The first stage may begin with a clay-sculpted 'positive' or 'male mold' of the character. A plaster mold is then made of the sculpture, capturing all of the detail. The plaster mold is generally made in two-pieces for a full-head mask. Another popular method of creating such masks is to make a life mold of the subject in which he or she reclines in a chair, has his or her hair protected by a skull cap, and has alginate placed over the head (breathing facilitated, typically, through straws placed in the nostrils). This is usually done in two parts—front and back. The division may be established through the use of a template of the top-to-bottom outline of the head and neck of the person being 'cast,' with a parting compound such as a lubricant being placed on the template to enable the easy separation and removal of the two parts of alginate. After the two parts have been removed and have been allowed to dry, they are re-united to form a 'female' mold into which plaster may be poured to re-create the image of the original cast head and features, in 'male' or 'positive' form.
Once the male or positive casting has been made the split external halves of the female mold is split off. The new 'positive' is carefully removed and cleaned. It may be altered through the superimposition of modeling clay that builds upon the original 'male' mold to establish different features for a final, external character mold that can itself be re-cast. Whether altered or not, the mold is re-cast to form a hollow negative of the design and latex rubber is poured in and allowed to sit for a short time before the excess is poured out.
After the latex rubber has dried inside the mold, it can be peeled out and painted as desired. What comes out of the mold is now the 'positive' version of the latex mask.
In complex transformations, both the original, unaltered positive mold and the altered, character molds may be used to achieve high levels of fit and fidelity. In such cases, thin 'takes' of both the changed and original may have the void between them filled with liquid latex so that the interior fits the original wearer and the exterior matches the desired character precisely.