Two methods of producing sparks of high brightness and short duration at high repetition frequencies are described. The circuits used are simplified versions of standard radar techniques and moderate voltages (5-10 kV), and standard components are used. The first method gives a limited number of discharges (four to eight) at individually determined time intervals of ten microsecond or greater with an error of less than one microsecond, and is intended for the production of superimposed photographs on a stationary film. The second method, used with a rotating drum or mirror camera, gives a greater number of light pulses at preset repetition frequencies up to 10 000 per sec. The energy of each spark is of the order of 1 joule, and the effective photographic duration less than 1 μsec. Adequate negative densities are obtained on process type emulsions at distances not greater than 1 metre. The elementary principles underlying the methods are briefly discussed and suggestions are made for increasing the flash energy and repetition frequency.