Posted 01/15/2014 5:42 pm
Okay, just to muddy the water a little bit...
The color names really began with fluorescent lights. Before I retired from the sign business, we dealt almost entirely with just two basic colors of white fluorescents, whether indoors or outdoors. They were Cool White and Daylight bulbs.
The term Cool White is misleading - it was not a cool color, towards the blue end of the spectrum. All it really meant was that the bulb was efficient, with less resistance in the tube, so it burned cooler. But the color of the light was actually WARMER! It was also considered a good choice when fluorescent lighting was combined with incandescent light bulbs.
The bulbs were sold by Westinghouse, Voltarc, and Philips. Each brand varied a little in color rendition, even though they shared the same color name.
The Kelvin color number is the best indication of the true rendition of the white light.
Cool White bulbs by Philips today are considered to be about 4100K. The actual range of CW bulbs is probably about 3500K to 4500K.
Daylight bulbs were closer to 6500K, and didn't have the warm or pinkish glow of CW bulbs.
So Cool White is a warm color.
It looks like LED lighting uses the same terminology today. (Much of the white neon tubing for neon signs uses the actual Kelvin numbers, and there too it varies by manufacturer and even by batch.)
-Duncan
The color names really began with fluorescent lights. Before I retired from the sign business, we dealt almost entirely with just two basic colors of white fluorescents, whether indoors or outdoors. They were Cool White and Daylight bulbs.
The term Cool White is misleading - it was not a cool color, towards the blue end of the spectrum. All it really meant was that the bulb was efficient, with less resistance in the tube, so it burned cooler. But the color of the light was actually WARMER! It was also considered a good choice when fluorescent lighting was combined with incandescent light bulbs.
The bulbs were sold by Westinghouse, Voltarc, and Philips. Each brand varied a little in color rendition, even though they shared the same color name.
The Kelvin color number is the best indication of the true rendition of the white light.
Cool White bulbs by Philips today are considered to be about 4100K. The actual range of CW bulbs is probably about 3500K to 4500K.
Daylight bulbs were closer to 6500K, and didn't have the warm or pinkish glow of CW bulbs.
So Cool White is a warm color.
It looks like LED lighting uses the same terminology today. (Much of the white neon tubing for neon signs uses the actual Kelvin numbers, and there too it varies by manufacturer and even by batch.)
-Duncan
Edited by Duncan_Doenitz
01/15/2014 5:50 pm
01/15/2014 5:50 pm
