Gray glass
The gray glass is an everyday aid of the lighting cameraman and the illuminator to see where the headlights hit. It looks like a tinted monocle and is usually worn around the neck on a cord.
application
1. Look directly into the lamp: Position yourself at the place where the lamp should later emit most of the light (spot). A second illuminator turns the lamp. If you look closely into the lamp, the light becomes significantly brighter and the lamp is set up. Without gray glass looking directly into the lamp, lamps from 18 kW would be too dazzling and would be harmful to health.
2. Look at the object to be illuminated: The gray glass expands the pupil like an ND filter (less light and larger light inlet ⇒ the same amount of light), which increases the perception of contrast. In this way, it is possible to determine relatively precisely how the brightness distribution is designed, even from a distance.