Photopic vs Scotopic

An important factor in measuring LED effectiveness is understanding the difference between Scotopic and Photopic vision in relationship to how the eye perceives light. (What is Scotopic and Photopic Vision?)

Seeing is believing: A recent study comparing the public’s perception of 100-watt HPS lighting vs. 75-watt LED lighting dramatically demonstrates the superiority of scotopic luminance. Scotopic vs. Photopic in Action: The Cree Garage Lighting Survey

Real-World Results
An experiment at the Intel Corporation’s multi-building campus in Hillsboro, Oregon, proved the scotopic-photopic theory. Described in Dr. Sam Berman’s article “The Coming Revolution in Lighting Practice,” Intel facilities staff observed during the study that one could see better under the scotopically rich lighting, and that this lighting was actually perceived as brighter even though a traditional light meter would indicate the opposite.

Intel realized they would achieve larger energy savings by reducing the number of lamps needed while at the same time improving overall lighting perception and effectiveness. In the campus’s eight buildings, scotopically enhanced lamps have yielded annual lighting energy savings of slightly larger than eight million kilowatt hours.