illumination converter
Unit Converters
1. Fundamental Definition:
E
=
ÎŚ
A
2. Unit Conversion (Lux â Foot-candles):
Elx
=
Efc
Ă
10.764
Efc
=
Elx
10.764
Illumination converter Table
| Unit | lux (lx) | kilolux | millilux | foot-candle (fc) |
|---|---|---|---|---|
| 1 lux (lx) | 1 | 0.001 | 1,000 | 0.0929031299 |
| 1 kilolux | 1,000 | 1 | 1,000,000 | 92.9031299064 |
| 1 millilux | 0.001 | 0.000001 | 1 | 0.0000929031 |
| 1 foot-candle (fc) | 10.7639 | 0.0107639 | 10,763.9 | 1 |
What is illumination converter?
Illumination, or illuminance, is a measure of how much luminous flux is spread over a given area. In simpler terms, it describes how "bright" a surface appears when light hits it. An Illumination Converter is a mathematical bridge used to translate these measurements between different systems, most commonly between the Metric (SI) unit, the Lux, and the Imperial unit, the Foot-candle.
Understanding the Values
E (Illuminance): This represents the intensity of light falling on a surface. It is different from "Lumen," which measures the total light emitted by a source.
Lux (lx): The SI unit of illuminance. One lux is equal to one lumen per square meter (1 lm/m²). It is roughly equivalent to the light of a full moon on a clear night.
Foot-candle (fc): A non-SI unit widely used in the United States, particularly in photography and architecture. One foot-candle is equal to one lumen per square foot (1 lm/ft²).
10.764: This is the geometric conversion constant. It represents the ratio of area between a square meter and a square foot (3.28084² â 10.7639).
History and Origin
The history of the illumination converter is a journey from the flickering flame of a candle to the digital precision of modern light sensors.
The Era of the Standard Candle
Before the 20th century, light was measured against a physical object: the Standard Candle. This was a specific candle made of spermaceti (wax from whales) that burned at a specific rate. A "Foot-candle" was literally the amount of light cast on a surface one foot away from one of these candles. As you can imagine, this was highly imprecise, as no two candles burn exactly the same way.
The Photometric Revolution
In the mid-1800s, scientists like Lambert and Bouguer began developing the laws of photometry. They realized that light intensity follows an Inverse Square Lawâif you double the distance from a light source, the illumination doesn't just halve; it drops to one-quarter. This discovery made the "area" part of the formula (E = ÎŚ/A) mathematically essential.
The Metric Shift
In 1948, the International Commission on Illumination (CIE) moved away from the "candle" and toward the "Candela," which was based on the light emitted by freezing platinum. This led to the formal adoption of the Lux as the international standard. Today, while architects in the U.S. might still specify a workspace at 50 foot-candles, a global manufacturer will use an illumination converter to ensure that the same space meets the international standard of approximately 538 lux. This ensures safety and comfort in environments ranging from surgical suites to film sets.
Frequently Asked Questions
How accurate is this illumination converter tool?
Our tools utilize high-precision floating point math guaranteeing accuracy up to the 6th decimal place.
Is this free to use?
Yes, all converters and calculators on ToolsMetrics are 100% free with no limits.