Oldtimers in the audience flinched when the curtain rose to reveal a meaningless shadowgraph sequence of Japanese town life, a very un-Gilbertian interpolation.
When Vina Delmar's Bad Girl was dramatized last season it contained one brief scene in which a childbirth was indicated by means of a shadowgraph.
The light, flashed through a region of disturbed air, recorded on a photographic plate a "shadowgraph" showing groups of bunched air molecules.