Illuminance
Illuminance is the total luminous flux incident per unit area. It refers to the amount of incident light.
Note that the expression for the amount of light "reflected" from a surface is luminance.
In SI derived units, it is measured in lux (lx) or candela steradian / metre squared
SI light units
| SI light units edit | ||||
|---|---|---|---|---|
| Quantity | SI unit | Symbol | Notes | |
| Luminous energy | lumen seconds | lm · s | lumen seconds are sometimes called Talbots | |
| Luminous flux | lumen or (candela · steradian) | lm | also called Luminous power | |
| Luminous intensity | candela or (lumen / steradian) | cd | ||
| Luminance | candela / square metre | cd/m2 | also called Luminosity | |
| Illuminance | lux or (lumen / square metre) | lx | ||
| Luminous efficiency | lumens per watt | lm/W | ||
| Missing image Balance_scale.jpg | This standards-related article is a stub. You can help Wikipedia by expanding it. |