Not Just Another Full Spectrum Bulb

By Matt Locker

Full Spectrum Fluorescent Lamps make an effort to replicate "noon sunlight", and some brands have come close to matching outdoor light on paper, but fail to recognize that the eye reacts very differently to 5500 Kelvin at outdoor levels, versus much lower indoor levels.

Full spectrum lamps fail to compensate for the eye's spectral roll off at indoor light levels. In the bright outdoors, this is a non-issue. however, at much lower indoor light levels, reds and blues are not passed to the brain at the same rate as green, This is because a notable amount of blue and red light is lost between the lens and the retina. To compensate for roll off, the lamp needs to be equalized by boosting red and blue.

The Skylighter (TM) is an HD EQUALIZED SPECTRUM lamp, compensating for lower red and blue eye absorption by boosting those areas of the spectrum. Because of the equalization, a true "outdoor" spectrum in perceived - at indoor levels. 

PICTURED BELOW ARE COMPARISONS OF BRIGHTNESS (AMPLITUDE) AND FREQUENCY RESPONSE (BANDWIDTH) FOR THE ACTUAL LIGHT SOURCE (LEFT) AND HOW WE PERCEIVE IT (RIGHT).

RED receptors are less sensitive than green receptors, blue light becomes scattered and loses strength as it passes through the eye..


TOP: Typical outdoor light exceeds the required threshold to saturate the R,G,B receptors, and no loss of red or blue is noticed.

MIDDLE: "Full Spectrum" lamps may produce a close duplicate of outdoor light, but at levels below the threshold of R,G,B saturation. Hence, the perceived waveform differs from the "replicated full spectrum" light.

LOWER: "HD Equalized Spectrum": Boosting the amount of red and blue normally lost by the eye in typical indoor light levels, The Skylighter preserves the frequency response, only at a lower amplitude.