ASENSETEK Spectrum Meter shows visible light spectrum with surprising amount of blue in a 4000K LED park ‘test’ fixture (2016).
Above: Chart shows the visible light spectrum of an incandescent light bulb at 2650 Kelvin. ASENSETEK Passport Spectrometer used on all spectrum and Kelvin analysis; learn more here.



possible as the technology

rapidly improves!

Light Emitting Diode (LED) light fixture.

Right: Thomas Edison invented the incandescent light bulb over 130 years ago. This shows a ‘standard light bulb’ with a light spectrum that is similar to a rainbow…with very little blue in the normal visible light spectrum.
CONSIDER 2700 KELVIN or lower FOR OUTDOOR LIGHTING. This is critical for LED lighting and is good for us plus the ‘night time wildlife’ which eat lots of insects.
This shows that 2700K LED light has about 25% less blue in the visible spectrum when compared to 3000K LED. (Note: this fixture was rated at 2863K.)
Above: The spectrum shows the blue contained in a 3000 Kelvin LED fixture. (Mountain View Park II, test in 2016.) Left: Is the spectrum of a 2700K fixture showing the significantly lower level of blue. were raised by residents, the Parks Director changed the specifications to 2700 Kelvin - for most uses! While over a dozen parks were already outfitted with 4000K LED lights it is hopeful that the department will be able to replace those fixtures soon. The City of Phoenix, Street Transportation Department, is replacing all the neighborhood 4000K LED lights with 2700K fixtures!
To avoid the harmful blue spike (above) unique to LED lights - CONSIDER 2700K LED for indoor and outside fixtures.
Above: The high pressure sodium (HPS) light bulbs are about 2200 Kelvin. Left: Colter Park with amber HPS lighting since the 1970’s - to save energy and they provided good sidewalk and playground lighting. The test fixture had harsh glare and bad blue LED rated at 4000 Kelvin.
HPS Amber lights in Park