:: You need something empirical, like a melanin count per square centimeter or some kind of light / color reading, like luminous flux or whatever's most appropriate.
12.
Spherical photometers can be used to measure the directional luminous flux produced by lamps, and consist of a large-diameter globe with a lamp mounted at its center.
13.
In comparison to conventional projectors, laser projectors provide a lower luminous flux output, but because of the extremely high contrast the brightness actually appears to be greater.
14.
The difference between the units " lumen " and " lux " is that the lux takes into account the area over which the luminous flux is spread.
15.
A full sphere has a solid angle of 4? steradians, so a light source that uniformly radiates one candela in all directions has a total luminous flux of.
16.
The luminous flux of xenon headlights in the Rapid models is 2, 000 lumens, so there is no need to install a headlight washer system or dynamic range adjustment.
17.
In this case, i . e . with the same luminous flux within the lens, the illuminance quadracially decreases and the luminous intensity quadratically increases with the image size.
18.
The standard ANSI IT7.215-1992 defines test-patterns and measurement locations, and a way to obtain the luminous flux from illuminance measurements, it does not define however a quantity named " ANSI lumen ".
19.
Luminous flux is not used to compare brightness, as this is a subjective perception which varies according to the distance from the light source and the angular spread of the light from the source.
20.
Smaller spheres are typically used to diffuse incoming radiation, while larger spheres are used to measure integrating properties like the luminous flux of a lamp or luminaries which is then placed inside the sphere.
