Illuminance Converter
Phot (ph)
Definition: A phot (symbol: ph) is a unit of illuminance in the older CGS (centimeter-gram-second) system. It is defined as one lumen per square centimeter, making it equivalent to 10,000 lux.
History/origin: The unit was formulated in the early 20th century as part of the CGS metric system. The name derives from the Greek word "phos," meaning light.
Current use: The phot is largely obsolete today, having been replaced by the SI unit Lux. However, it is still occasionally found in older scientific literature or highly specific physics applications.
Lux (lx)
Definition: The lux (symbol: lx) is the SI derived unit of illuminance and luminous emittance. It measures luminous flux per unit area and is equal to one lumen per square meter.
History/origin: The unit comes from the Latin word "lux," meaning light. It was introduced in 1889 and formally adopted into the International System of Units (SI) to provide a standard measure for human-perceived light intensity.
Current use: Lux is the universal standard used to measure indoor and outdoor lighting levels, workplace safety lighting standards, and environmental lighting for plants and animals.
Phot (ph) to Lux (lx) Conversion Table
| Phot (ph) [ph] | Lux (lx) [lx] |
|---|---|
| 0.01 ph | 100 lx |
| 0.1 ph | 1000 lx |
| 1 ph | 10000 lx |
| 2 ph | 20000 lx |
| 3 ph | 30000 lx |
| 5 ph | 50000 lx |
| 10 ph | 100000 lx |
| 20 ph | 200000 lx |
| 50 ph | 500000 lx |
| 100 ph | 1000000 lx |
| 1000 ph | 10000000 lx |
How to Convert Phot (ph) to Lux (lx)
1 ph = 10000 lx
1 lx = 0.0001 ph
Example: convert 15 ph to lx:
15 ph = 15 × 10000 lx = 150000 lx
Did You Know?
- A Phot (ph) is an extremely bright unit of measurement. Just one Phot is equal to 10,000 Lux, which is roughly equivalent to the lighting used in professional TV broadcasting studios.
- Did you know? Direct, bright sunlight can measure over 100,000 lux, while a typical well-lit office is around 500 lux. On a clear night, the full moon provides only about 0.1 lux of illumination!