The relationship between illuminance and luminosity and distance is: E (illuminance) = I (luminosity) / r2 (distance squared).

The illuminance of the illuminated body is related to the luminous intensity of the light source and the distance between the illuminated body and the light source, but not to the color of the illuminated body, the nature of the surface and the size of the surface area.

In the dining space, in the indoor environment and table tops must have enough light to meet the basic needs of customers dining, according to the China Lighting Association in China's architectural lighting design standards recommended that the table illuminance to 200lx is appropriate.

Expanded

Luminous intensity commonly used unit for candela (cd, candela), the international standard candela (lcd) is defined as an ideal black body at the platinum freezing point temperature (1769 ℃), perpendicular to the black body (its surface area of 1m2) direction of the 600,000th part of the luminosity,

the so-called ideal Blackbody is the object's emissivity is equal to 1, the energy absorbed by the object can be all radiated, so that the temperature has been kept uniformly fixed, the international standard candle (candela) and the old standard candle (candle) of the interchangeable relationship of 1candela = 0.981candle

Baidu Encyclopedia - Luminous Intensity