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.
GOOD LIGHTING FOR STREETS,
PARKS & NEIGHBORHOODS is
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