Dillon Arms

Shadowgraph Photography

Shadowgraph technique

The bullet, passing at a close distance in front of a photographic film plate is illuminated by a short duration light flash, which must be concentrated in a point. The flash can be triggered by a light barrier for example. No camera or optical lens is required for this technique. The shadowgraph displays the flowfield structure in the vicinity of the moving body.

Some typical set-up parameters of an experiment are:

Distance of bullet to film plate a few centimeters
Distance of point spark light source to film 2 - 3 meters
Flash duration 1 ms or less
Film 100 ASA