ASISTM Project Forensic Investigations Impressions

Shoeprints The physical contact between the shoe and the surface results in a transfer of the individual characteristics of the shoe. Shoes prints are often used to prove that suspect was present at a crime scene.

3-dimensional impressions Footwear impressions are pressed into a soft surface such as mud. The impression is influenced by the weight of the person and the type of surface.

Casting a 3-dimensional impression Photography Paul Ricketts, 2006

Sports Shoes Photography Paul Ricketts, 2006

Boots Photography Paul Ricketts, 2006

Lady’s shoes Photography Paul Ricketts, 2006

Using Alginate to make an impression 1 - alginate powder Photography Paul Ricketts, 2006 2 - pour the alginate into a plastic bag 3 - about 1/3 of a bag

5 - squish the powder and water 4- add water 5 - squish the powder and water 7 - cut a small hole at a corner of the bag with scissors 6 - thoroughly mix Photography Paul Ricketts, 2006

8 - squeeze out the alginate onto the impression. Work quickly as alginate dries very fast. 9 - carefully pat into place 10 - the alginate changes colour when dry - carefully lift from the impression Photography Paul Ricketts, 2006

The finished impression 10 - wash away as much dirt as possible Pict of finished impression - to do Photography Paul Ricketts, 2006

2-dimensional impressions 2-dimensional impressions occur when an image of the print is left on the surface. Some 2-dimensional impressions are highly visible – muddy footprints on a cleaned floor – while others are latent or invisible.

2-dimensional impression: Blood Photography Paul Ricketts, 2006

Latent 2-dimensional impression: luminol Photography Paul Ricketts, 2006

Other impressions Casts can be taken of the impressions of other objects. Eg, tyre tread

Tyre tread Photography Paul Ricketts, 2006

Tyre tread on ground Photography Paul Ricketts, 2006

References Images All photography by Paul Ricketts, DUIT Multimedia, the University of Western Australia. J. Baines is the model for the sequence of photographs showing taking a shoeprint impression using Alginate. Shoes supplied by J. Dook. Graphic design of slides by Trevor Hutchison, DUIT Multimedia, the University of Western Australia.