Problems with Foot-candles, Lux and Lumens.

The article focuses on need of light measurement unit with the increasing use of light emitting diodes (LEDs) and importance of light for plant growth and photosynthesis. Topics discussed include three ways to describe light intensity includes photometric which is the number of lumens per watt of energy, radiometric which is used to determine energy input and output of lighting applications, and quantum based on the Stark-Einstein Law.