"Warm White" or Yellow LED Reading Light?
July 27, 2015 10:21 AM   Subscribe

I try to reduce blue light at night and am looking for an LED reading light that has a warm color.

The best I could find on Amazon was a light rated at 3000K, but I was hoping for something closer to, or lower than, an incandescent (which I understand is 2700 K). And there was a question last year on this topic but answers were geared to a DIY solution. I'm looking for something off-the-shelf.
posted by Jon44 to Technology (10 answers total) 2 users marked this as a favorite
This online seller has bulbs categorized by color temperature.
posted by orme at 10:32 AM on July 27, 2015

This may sound silly but can you clarify what you mean by "reading light"? Like, does it have to clip onto a book or can it be a small thing that sits on a table? Or mounts on a headboard?

I feel your pain and strongly prefer lights in the 2700K range; generally I have had no trouble finding compatible LED bulbs and would be glad to suggest some, but I want to make sure I'm focusing on your actual problem.
posted by Joey Buttafoucault at 10:42 AM on July 27, 2015 [2 favorites]

Are you concerned about the effect of blue light on melatonin production, or are you interested in reducing blue light for aesthetic reasons?

White LEDs are actually kind of a hack on our color vision, and even a "warm white" LED produces a lot more blue light than you might expect based on its appearance.

Flames, the sun, incandescent bulbs, and other lighting technologies based on making something really hot all produce photons at a range of frequencies distributed along what we call the "black-body curve", which has a peak toward the high-energy end and a long, fat tail down through infrared. Making the light source hotter moves its spectral peak more toward blue, and making it cooler moves the peak toward red. The idea of color temperature assumes that we are talking about some hot object emitting the charactersitic range of light frequencies you would expect for how hot it is.

LEDs work in a completely different way and the light they emit does not follow the black-body curve at all. Instead of generating full-spectrum light, a white LED actually works by faking out your color vision: it emits narrow peaks of light which precisely stimulate human color receptors in a careful balance, exactly as they would be stimulated by full-spectrum light on the black-body curve.

White LEDs are actually all blue LEDs at heart, and they all produce a sharp spike of light at around 430 nanometers, which is right on the edge of the range that suppresses melatonin production. These LEDs *appear* to be white because they are coated with a layer of phosphor, which absorbs some of these blue photons and re-radiates them as yellow-orange photons. This is what the resulting spectral curve looks like; we describe such light using color temperature numbers in order to compare the subjective effects, but an LED which produces "2700K"-appearing light has a spectral shape which includes a great deal more blue light than an incandescent light at 2700K.

As a result, current research suggests that LEDs tend to suppress melatonin production, more than other types of lights.

Now.... the interesting thing is that this only holds for fixed-color white LEDs. If you get a color-changing LED, that works in a completely different way: it actually has three completely separate LED elements inside, and it produces different colors by adjusting the ratio of red/green/blue light. If you can set this kind of lamp to produce orange-yellow light, it will do that by turning the blue element down or off, leaving only the lower-frequency red and green LEDs active. NASA is doing some research on the ISS to see if this solves the melatonin problem.
posted by Mars Saxman at 2:28 PM on July 27, 2015 [5 favorites]

This Edison-style LED bulb is 2200K and also dimmable. If you're in the US, they stock these at Home Depot. I recently got one for my bedroom, and while it looks a bit silly when it's off, to me it's a dead ringer for incandescent Edison bulbs.
posted by Drosera at 4:52 PM on July 27, 2015

Response by poster: Thanks for the responses.

I was thinking, ideally, of a clip-on, battery-powered portable reading light, but based on info here, I think it's going to be impossible to find what I'm looking for. (I am interested in reducing blue light on account of interruption of melatonin.)

Seems like best solution is an incandescent reading lamp with an amber bulb for home, and headlight with red light for travel. (Or regular light with blue-block glasses.)
posted by Jon44 at 5:31 AM on July 28, 2015

I use Phillips Hue bulbs for all my blue-light-melatonin-related needs. I set it up to automatically shift color temperature at the appropriate times. Not cheap, but super effective, plus it allows you to use your whole bedroom as a giant sunrise alarm.
posted by oblique red at 3:19 PM on July 28, 2015

You'll look like you're on a job site, but you can get these blue light-blocking glasses and wear them an hour or two before bed.
posted by 4midori at 8:52 PM on July 28, 2015

Best answer: Check out this site: https://www.lowbluelights.com/
posted by islandeady at 10:04 AM on July 31, 2015

Response by poster: Coincidentally, "lowbluelights.com" just came out with clip-on reading light with amber LED's. Just what I was looking for... Thanks.
posted by Jon44 at 10:35 AM on August 1, 2015

Amber book lights are my favorite sleep aid!

I actually review lights and light therapy devices for my blog, LightTherapyReviews.net, so I’ve bought the only two (as far as I know) single-color amber book lights available, one from lowbluelights and Somnilight. The Lowbluelights book light has 18 tiny orange LEDs arranged in a circular design, while the somnilight book light has four slightly larger amber LED’s in a dual head design.

The Lowbluelights model has an A/C adapter, while the Somnilight includes an usb adapter for direct power, but the short lengths of both cords makes using them less than ideal. In terms of battery life, somnilight is the clear winner with about twice the lifespan for a set of batteries. The Lowbluelights book light has a slightly more orangish glow than the Somnilight, but both claim to emit only amber wavelengths. Both book lights are currently $30, though the cost of shipping might differ. On the whole, I preferred the somnilight book light, though I’ve bought some great amber screen filters from Lowbluelights.

As a self-appointed light therapy expert, I agree with a previous poster: even warm incandescents contain too much blue light for nighttime use. Switching to amber book lights at night has helped my insomnia immensely.
posted by AdAstra1952 at 8:09 PM on January 12, 2016

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