Criminalist, Contra Costa County Criminalistics Laboratory, Martinez, CA
(Received 14 March 1983; accepted 11 April 1983)
Sulfur has, up to now, been the medium of choice for casting shoe and tire impressions in snow. Even under perfect conditions casting impressions in snow using sulfur results in some melting, giving the resultant casts a somewhat porous appearance with corresponding loss of the original detail. A new product developed in Sweden can be used to avoid these problems. It gives casts that have considerably more detail than sulfur casts. The new method employs a two-step process. First, a layer of Snow Print Wax® aerosol is sprayed over the whole impression and allowed to dry. Second, a viscous mixture of plaster of paris and water at 25°C is poured into the impression. The plaster of paris is covered with layers of newspaper to keep it from freezing. When the casting material has set, the cast is removed from the snow. The wax layer adheres to the plaster.
Paper ID: JFS11667J