Commentary

Comparing light spectra: sunlight vs. artificial light sources. The following illustrations were obtained through a detailed process. Light was passed through a spectroscope (light analyzer), then recorded with a camcorder and transferred into a computer via a coupling device (Snappy©). After adjusting size and format, the images were moved into our website system. While accurate, the brilliance of a live spectroscope view can never be fully reproduced digitally.

The first spectrum was captured at noon in New Jersey on a sunny May day. It shows the full range of visible frequencies from red through violet (not including the invisible infrared or ultraviolet).

The second spectrum is that of a neodymium-filtered bulb. Human vision is naturally more sensitive to yellow frequencies, so removing them may create what some call a “more soothing” light. Even so, how can neodymium bulbs be honestly labeled as “full spectrum”? Chromalux© claims to “closely mimic Nature’s Sunlight.” Compare the two graphs and judge for yourself. GE Reveal© also claims to remove the “dull yellow rays,” which we consider an advertising stretch. Life on Earth has done quite well with the sun’s spectrum; attempts to “improve” it seem rooted more in misunderstanding—or marketing—than science.

The third spectrum is from an OttLite© fluorescent bulb, another product labeled as “full spectrum.” Fluorescents typically contain both missing energy areas and narrow spikes of intense emission—not fully depicted here due to their strength. Emission graphs are often “smoothed” to make the output appear similar to sunlight. Common compact fluorescents emit nearly the same pattern. While efficient, they may pose long-term health tradeoffs.

Standard household incandescent bulbs share a similarity with sunlight—no major emission gaps or peaks. However, they are heavily weighted toward the red end of the spectrum. Until LED or dichroic reflector bulbs improve, we recommend incandescent bulbs when necessary, and sunlight through open windows whenever possible. Some individuals may feel better using these unbalanced sources because they mimic a color tonation where certain frequencies are amplified. Over time, however, what once helped can become an overload.