An automatic system has been developed to take flash photomicrographs of the roots of notches in flat doubly-notched specimens during low cycle fatigue tests to determine the cyclic time of crack initiation. The photomicrographs are taken on 35-mm film periodically during the test at preprogrammed cyclic intervals without interrupting the cyclic loading procedure, until a well-defined crack has formed and extends across the full thickness of the specimen at the notch root. In making the data analysis, the developed negatives are projected on a screen at a magnification of approximately 100, and the final well-defined crack is traced backwards in “time”, frame by frame, to its initiation. A crack is judged to have just initiated when it is visible in one frame and not evident in the frame just preceding. Cracks with a surface length of 0.001 in. (0.025 mm) and an opening of 0.0001 in. (0.0025 mm) are easily visible in the projected images.