A camera flash apparatus having a flash tube enclosing a pair of
electrodes in an ultraviolet light transparent envelope containing gas
molecules normally presenting a high impedance between the electrodes. An
ultraviolet light source directed at the tube is actuated at the start of
a flash picture-taking event to ionize at least some of the gas in the
envelope lowering the internal resistance of the tube to allow a flash
energy source coupled to the electrodes to discharge through the flash
tube. A flash unit incorporating the ultraviolet source is also disclosed