What Is a Foot Candle Meter?

Luminance (luminance), also known as luminosity , refers to the brightness of a surface, represented by L, that is, the luminous flux reflected from a surface. In other words, it refers to the luminous intensity of a surface light source with a unit projected area in a certain direction in that direction.

brightness

Auxiliary memory :

It refers to the brightness of the luminous surface, which refers to the ratio of the luminous intensity of the luminous surface in a specified direction to the area of the luminous surface perpendicular to the specified direction. The unit is candela / square meter.

For a diffuse scattering surface, despite the light intensity and

Different objects have different effects on light

The relationship between brightness and illuminance. The most commonly used unit of illuminance is

There are also several units of measurement for brightness. The unit of brightness is defined by an idealized standard state. Use a standard candle as the light source and place it in the center of a sphere with a radius of 1 meter. Assuming that this candle will evenly distribute all its light, the amount of light falling on one square meter of surface area on the surface of the sphere is 1 lumen. In practical applications, the luminance unit is too small in lumens, so it is usually expressed in units of ten times-millilambert. A unit larger than a milli-Lambert is a foot-lambert (foot-lambert), and a milli-lamber is equal to 0.929-foot-lambert.

The British standard foot Lambert is specified by the number of candles of a light source, the number of feet from the light source to the surface area, and the surface reflectance. In some countries, metric units are commonly used and are based on milli-Lamberts

1 milliamp Lambert (mL) = 0.929 feet Lambertian (ftL) = 3.183 candlelight / square meter (c / ) = 10 apostilbs

Units of brightness are: candela / square meter (ie, Nit, Nit = 1cd / ).