IES TM-1-12

Every discipline has its own special terminology and lighting is no exception. Fortunately, in lighting, there are only five basic metrics that need to be learned; unfortunately, they have similar names and unusual units, and may be a challenge for a beginner in lighting to comprehend and understand.

For those readers new to lighting but not to the broader field of electromagnetic radiation, light is defined as radiant energy that is capable of exciting the retina and producing a visual sensation.