Color Temperature and Productivity

This article in Grokcode.com summarizes papers from The Journal of Circadian Rhythms and Applied Human Science regarding color temperature and productivity. The author, Jess Johnson says that cool color temps are better for working.

Well, they could also use uncomfortable chairs and that would promote "alertness" too or chalkboard screeching sounds as ambient background music. Wonder what the retention rates are.

This matches my own experience. In all honestly, low color temperature, incandescent-type light literally puts me to sleep. I don't use it anywhere. 5000K is my general purpose lighting. I might try 6500K where I work to see if it's any better than 5000K. Not sure I would want to do anything under 17000K, but that might be worth a try also.

I'm finding the productivity versus temperature part even more interesting. The most basic finding is higher temperatures lower productivity. This explains why the economies of warm countries are lousy, at least until they can afford air conditioning for most of their work force. Again, it matches my experience perfectly. Summers I pretty much can't do anything remotely productive on account of the heat, even with A/C. The A/C makes a little difference (basically the difference between lying in bed all day versus doing something, even if that something is just watching TV or surfing the Internet). You'll never get me to move to a hot place.

Interesting study.

Still can't beat good ol' sunlight for getting things done, another reason to work outdoors..

jtr1962 said:

Summers I pretty much can't do anything remotely productive on account of the heat, even with A/C. The A/C makes a little difference (basically the difference between lying in bed all day versus doing something, even if that something is just watching TV or surfing the Internet). You'll never get me to move to a hot place.

Click to expand...

It's the humidity, not the heat; out here in the single-digit-humidity desert, even when the temps nudge 100 degrees, as long as you're in the shade with even a tiny breeze, it's entirely comfortable.

When you sleep in daylight, what is the color temperature of the light after being filtered through your closed eyelids? Maybe, 1000 K? Duh, no wonder!

jtr1962 said:

Not sure I would want to do anything under 17000K, but that might be worth a try also.

Click to expand...

Seventeen THOUSAND K?? What's that, a black light?? X-Rays maybe?

(Goes off to boggle quietly )

Interesting subject, but there must have been better research on it.

Gr*kc*de is trying to benefit from the sales of bulbs, and is using the term "scientifically proven" -- which directly translates into "junk text, don't bother to read!"

http://www.jcircadianrhythms.com/content/5/1/2
paper states:
"Competing interests
LS is an employee of Philips, which provided the lights for the study."

"This study was funded by an unconditional educational grant from Philips Lighting, which also manufactured the high correlated colour temperature fluorescent lamps used for the intervention."

Thanks for the honest declaration, this may in part explain the lousy study design. (at first glance: the selected illumination level may show a stronger effect of high-CCT lamps than higher levels; participant self selection; subjective performance criteria).

Anyway, one of the more significant issues about shift work lighting is cancer risk from melatonine suppression, and this long-term health topic runs against the short-term interest of the current marketing and application of high-CCT, "rat-race enhancing" lamps.

I do a lot of corporate consulting, and work under a lot of lighting conditions. I'd have to say my favorite for general activity is around 5000k *high* CRI. Low CRI daylight tubes are annoying after awhile and I've noted tend to make people edgy (lack of red?).

So there's a discussion over at a low carb forum on insomnia, sleep issues etc., and lightbox therapy came up. Looked it up and found a couple of interesting articles:

Light Box Use for Phototherapy to Treat Circadian Disorders and SAD 11-3-19

Light Box Therapy 9-8-19

Does anyone here use a lightbox? The idea is not getting enough 10,000 lux sunlight during the morning / day which is crucial for setting the bodies circadian rhythm and setting you up for a good nights sleep. They used them up in Norway etc. Maybe in predominately cloudy areas such as the Pacific Northwest? This coincides with the use of sunglasses in the morning, which delays the body waking up and can delay sleepiness when you are ready at night.

I wonder what the color temperature is for these lightboxes?