The main objetive of this thesis is to evalute in a quantitative manner the possibility of employing photoplasticity as na experimental techinique for the predection of large plastic strains which occur in mechamnical forming. This was made throught an experimental study of the plane extrusion problem. Distribuitions of strains obtained through the photoplastic analystic were compared to those obtained by the grid technique in plane models made of spoxy and polyester resinds, lead and aluminum. Trying to determine the polymer that best reproduces the mechanical behavior of other materials commonly used in forming processes, several combinations of rigid and flexible polyester resins and a new formulation of a epoxy resin still in development ere studied when submitted to plane extrusion. The results were compared with those obtained from aluminum and lead models subject to the same mechanical process. Although, other combinations of polyester resind present satisfactory results, it was verifyed that the combination of 70 per cent rigid and 30 per cent flexible polyester resins was teh one that best modeled the plastic strains that occurred in the plane extrusion of the aluminum and lead specimens, if appropriate correction factors were aplled to take into account the plastic strain recovery which occurs right after unloading of the polyester specimens.