sensitometer

Małachowski in 1880 invented the first practical sensitometer, which allows measurement of the speed of photographic materials.

Leon Warnerke aka Władysław Małachowski, inventor of the first practical sensitometer in 1880.

It is also equipped with a spectral prism with a prime angle of 6.10 degrees for stellar spectra, a wedge sensitometer and a film recorder.

The Warnerke Standard Sensitometer consisted of a frame holding an opaque screen with an array of typically 25 numbered, gradually pigmented squares brought into contact with the photographic plate during a timed test exposure under a phosphorescent tablet excited before by the light of a burning Magnesium ribbon.