Corona discharge photography

Using short (∼ 100 μsec) pulses of rf (1 MHZ) applied to parallel electrodes in air at small electrode spacings (∼ 250 μ) and at an applied field of ∼ 106 V/cm, discharges from both biological and metallic electrodes occurred from a network of points in the electrode surface. These discharges were recorded photographically. Multiple pulses lead to a superposition effect such that a uniform corona exposure appeared on the film. Some effects of electrode material, spacing, and orientation are presented. The results are found to be completely explicable in terms of the ``streamer'' phenomenon of corona discharge. In fact, the wide variety of color effects observed in ``Kirlian'' photography can be accounted for by this mechanism.