Holographic interferometry is a very efficient technique used in non-destructive testing and characterizing of composites. Many kinds of defects may be simultaneously detected over large areas, without any contact with the tested material. All the defects appear as local distortions of a regular fringe pattern covering the holographic image of the tested object. Seeing a complicated fringe pattern with a large number of local distortions in a single image might be confusing for the operator, who is often interested in detecting a particular type of defect. In such cases, in order to apply the holographic technique, specialized testing techniques have to be established. This paper describes two such techniques, one for testing the metallic insertions in the belt area of rubber tyres, the other for testing pasteboard-epoxy composites, and detecting fiber direction and interactions.