Abstract: A tensile testing system for use with a specimen of rubber or other material having a test region defined on its reduced midportion by a marking or markings of, for example, higher lightness than the other specimen surface. The system comprises a scanning device for repeatedly translating the optical characteristics of the specimen or specimens into an electrical signal as the specimen or specimens are subjected to increasing tensile stress, and a gate circuit for deriving from the output signal of the scanning device its portions corresponding to the test region or regions. The varying length of the test region or regions can be represented either by pulse durations or by pulse numbers. The scanning device can be either an "area scanner" such as a television camera or a "line scanner" such as a solid-state line image sensor. Various embodiments are disclosed.