Amédée Jobin’s universal photometer (1920)

Amédée Jobin developed a universal photometer without a diffusing screen. This device, designed by physicists Henri Buisson and Charles Fabry, is capable of measuring the intensity of a light source without interference from other sources or surrounding diffusing bodies, allowing for easy measurement of the intensity of sources with low luminosity or very distant sources. The same applies to the measurement of the brightness of a surface or illumination, and to the evaluation of light loss in an optical instrument.