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Claims about the benefits of full-spectrum light sources abound. They have been credited with everything from productivity improvements to retail sales boosts, from treating seasonal affective disorder (SAD) to sleep disorders.

Separating scientific evidence from marketing claims was one of the goals of the National Lighting Product Information Program's (NLPIP) in-depth look at full-spectrum light sources.

The result is an 18-page "Lighting Answers" document recently published by the NLPIP. The report was co-authored by Mark Rea, Lei Deng and Robert Wolsey of the Lighting Research Center

Among the findings of "Lighting Answers: Full-Spectrum Light Sources" are the following:

All "full-spectrum light sources" are not created equal. They differ depending upon each manufacturer's definition;
The term "full-spectrum" is a marketing term, not a technical one.
Full-spectrum light sources will probably provide excellent color rendering.
Under most circumstances, full-spectrum light sources will not provide better visual performance than other light sources.
Full-spectrum light sources will not provide better health than most other electric light sources.
Full-spectrum light sources may have psychological benefits. The authors find this to be the case particularly in societies that place value on "natural" environments.
Most lamps bearing the "full-spectrum" name are relatively less energy-efficient than fluorescent lamps.
To learn more about the NLPIP's findings-including the light sources that can be categorized as full-spectrum-read the full report.