Orders of magnitude (illuminance)
Comparison of a wide range of brightnesses
From Wikipedia, the free encyclopedia
As visual perception varies logarithmically, it is helpful to have an appreciation of both illuminance and luminance by orders of magnitude.
Illuminance
To help compare different orders of magnitude, the following list describes various source in lux, which is a lumen per square metre.
| Factor (lux) |
Multiple | Value | Item |
|---|---|---|---|
| 0 | 0 lux | 0 lux | Absolute darkness |
| 10−4 | 100 microlux | 100 microlux | Starlight overcast moonless night sky[1] |
| 140 microlux | Venus at brightest[1] | ||
| 200 microlux | Starlight clear moonless night sky excluding airglow[1] | ||
| 10−3 | 1 millilux | 2 millilux | Starlight clear moonless night sky including airglow[1] |
| 10−2 | 1 centilux | 1 centilux | Quarter Moon |
| 10−1 | 1 decilux | 2.5 decilux | Full Moon on a clear night[1][2][3] |
| 100 | 1 lux | < 1 lux | Extreme of darkest storm clouds, sunset or sunrise |
| 101 | 1 decalux | 40 lux | Fully overcast, sunset or sunrise |
| 102 | 1 hectolux | < 200 lux | Extreme of darkest storm clouds, midday |
| 400 lux | Sunrise or sunset on a clear day (ambient illumination) | ||
| 104 | 10 kilolux | 10–25 kilolux | Typical overcast day, midday |
| 20 kilolux | Shade illuminated by entire clear blue sky, midday | ||
| 105 | 100 kilolux | 110 kilolux | Bright sunlight |
| 120 kilolux | Brightest sunlight |
Luminance
This section lists examples of luminances, measured in candelas per square metre and grouped by order of magnitude.
| Factor (cd/m2) |
Multiple | Value | Item |
|---|---|---|---|
| 10−6 | μcd/m2 | 1 μcd/m2 | Absolute threshold of vision[4] |
| 10−5 | |||
| 10−4 | |||
| 10−3 | mcd/m2 | 100 μcd/m2 | Cloudy night sky without moon[4] |
| 400 μcd/m2 | "Darkest sky"[5] | ||
| 1 mcd/m2 | Night sky[6] | ||
| 1.4 mcd/m2 | Typical photographic scene lit by full moon[7] | ||
| 10−2 | 5 mcd/m2 | Approximate scotopic/mesopic threshold[8] | |
| 10−1 | |||
| 100 | cd/m2 | 2 cd/m2 | Floodlit buildings, monuments, and fountains[9] |
| 101 | 5 cd/m2 | Approximate mesopic/photopic threshold[8] | |
| 25 cd/m2 | Typical photographic scene at sunrise or sunset[7] | ||
| 30 cd/m2 | Green electroluminescent source[5] | ||
| 102 | 55 cd/m2 | Standard SMPTE cinema screen luminance[10] | |
| 80 cd/m2 | Monitor white in the sRGB reference viewing environment | ||
| 250 cd/m2 | Peak luminance of a typical LCD monitor[11][12] | ||
| 700 cd/m2 | Typical photographic scene on overcast day[7][9][12] | ||
| 103 | kcd/m2 | 1 kcd/m2 | Cloudy sky at noon[4][12] |
| 2 kcd/m2 | Average cloudy sky[5][12] | ||
| 2.5 kcd/m2 | Moon surface[5][6] | ||
| 3–5 kcd/m2 | Clear sky[6][12] | ||
| 104 | 5 kcd/m2 | Typical photographic scene in full sunlight[7][9] | |
| 8 kcd/m2 | Average clear sky[5][12] | ||
| 10 kcd/m2 | Clear sky at noon[4][12] | ||
| 10 kcd/m2 | White illuminated cloud[6] | ||
| 12 kcd/m2 | Fluorescent lamp[5][6] | ||
| 105 | 75 kcd/m2 | Low pressure sodium-vapor lamp[6] | |
| 130 kcd/m2 | Frosted incandescent light bulb[5][6][12] | ||
| 106 | Mcd/m2 | 600 kcd/m2 | Solar disk at horizon[5] |
| 107 | 7 Mcd/m2 | Filament of a clear incandescent lamp[13] | |
| 108 | 100 Mcd/m2 | Possible retinal damage[4] | |
| 109 | Gcd/m2 | 1.6 Gcd/m2 | Solar disk at noon[5][6] |