The moulage is cast with the aid of a plaster negative or, nowadays, silicone. For this purpose, an impression, is taken from the corresponding skin surface. In casting, the negative is filled with the warm, liquefied moulage mixture and then separated from the moulage in a water bath.
The moulage mixture, according to the recipe brought to Zurich by Lotte Volger in 1918, consists of bleached beeswax, dammar resin and calcium carbonate (Note: In chemical analysis of Zurich moulage mixtures, however, hardly any resin could be detected. The composition of the wax mixture used has been the subject of research in the context of the conservation of these valuable objects.). Before casting, the mixture is dyed with the oil colours madder varnish, cobalt, bitumen and gamboge dissolved in turpentine oil according to the patient’s lightest skin tone.
Small corrections are made with a hot modelling iron or scalpel, and various additions like scabs, scales, or blisters may be modelled and attached separately. Wax mixtures, varnishes, resins, glues and other auxiliaries are used to reproduce these efflorescences. Hair must be inserted individually into the moulage and must match the patient's hair.
In a next step, by daylight or with the aid of a daylight lamp, the colouring of the skin disease is painted directly onto the moulage. Again, only the above-mentioned oil colours dissolved in turpentine oil are used, and then applied to the moulage going from the lighter to the darker shades. Soft colour transitions are achieved by blotting with fine brushes.
Traditionally, the moulage is melted onto a black wooden board and lined with a white strip of fabric. As a rule, the diagnosis, a moulage number and the manufacturer of the moulage are also noted on the