Schumann plate

Schumann plate

[′shü‚män ‚plāt] (graphic arts) A type of photographic plate in which the silver halide is held to the glass, using a special method, by a layer of gelatin so thin that it is transparent to ultraviolet light with wavelengths as short as 1200 angstroms (120 nanometers), in contrast to the limit of about 2200 angstroms (220 nanometers) in a conventional photographic plate.