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 |
