Warming up cool LEDs

October 8, 2018 10:44 AM

I have a smattering of small home lighting devices that are cool white, a color of light that makes me slightly nauseated, but I hate to just throw all these things away or shove them in a back of a drawer. Can they be DIY'ed warmer?

None of these are family heirlooms (you know, like all those LED family heirlooms one has), but they work and I hate to throw them out or just pile them up somewhere. These are things like clip-on reading lamps, little cheapy desk lamps, several nightlights, undercabinet strips.

I did do an experiment yesterday with a nightlight and gold washi tape on one half and a wash of thinned carrot-colored acrylic paint on the other, both of which only highlighted how incredibly BLUE and GREEN cool light is (and how green my gold washi tape is). There is probably some sounder Art Science I could apply here, along with craft supply science (I have tons of random shit, would buy more in the name of experimentation). None of these are super bright and most of them are already covered in some kind of frosted plastic as I loathe a naked light filament/diode, and I'm trying to lose as few lumens as possible in my modifications.

Thougts? Material suggestions?

posted by Lyn Never to Home & Garden (11 answers total)

You could get some lighting gels and experiment to see which one warms up the light to your taste. You can cut the gels to fit your lights.
posted by erst at 10:58 AM on October 8, 2018 [3 favorites]

Tilt harder at warm colors? Red paint covering, red washi tape, maybe even additional red LEDs. Too much filtering might make the LED dim beyond usefulness.
posted by Maecenas at 11:01 AM on October 8, 2018

Most of the problem lies in the fact that the LED bulbs don't produce enough in the red part of the spectrum. Usually there are just blue LEDs inside, which produce light that gets magically transformed to white light by a phosphor coating. The coating determines the characteristics (the 'colour temperature') of the light that gets emitted into your room.

The only way you can make your cool white bulbs appear 'warmer' is to block some of the blue light that's being emitted from the phosphor. While this will give you a 'warmer' colour, it'll also greatly reduce the overall brightness. It's a lossy process.

Best thing might be to donate all of the bulbs you don't like to someone who isn't fussy (or can't afford to be), and then buy some good quality 2700-3000K bulbs (2700K is very warm, 3000K is the standard 'warm white')
posted by pipeski at 11:04 AM on October 8, 2018 [9 favorites]

Since these are small, and if they are AC powered, I might guess that your nausea is caused by imperceptible 120 Hz flicker synced with 60Hz AC rather than color by itself (color could still be in a supporting role because blue-sensitive cones have the fastest response times).

In that case, I don't think there's anything you could do that would be worth the effort.
posted by jamjam at 11:15 AM on October 8, 2018 [2 favorites]

The flicker could even be 60 Hz, depending on the arrangement of the LEDs.
posted by jamjam at 11:18 AM on October 8, 2018

Find a shop or website that sells lighting gels for theatre and film, and get the sample swatchbook for all the gel colours offered by a brand (Rosco for instance).

Then cut out gels in different warm colours and experiment with taping them over your lights. You might be able to mosaic little squares of different warm colours to make pieces that are the right size, or you may find a single colour you like and then you could just order a sheet(s) of it.
posted by pseudostrabismus at 11:22 AM on October 8, 2018

I detest the cool white LED color. It reminds me of parking structure lighting: harsh and very unpleasant.
I have ended up scrapping (donating) the cool white LED items I had and rebought warm white. The warm white options are far more prevalent now than they were even a couple of years ago. Fiddling with gels and paints and tapes will cost money and still may not solve the problem. I did a lot of experimenting with colored cellophane and paint before giving up. Nothing was really satisfactory while also letting enough light out. Freecycle or Habitat for Humanity are places where you can give away still-working items to others in need.
posted by quince at 11:43 AM on October 8, 2018 [1 favorite]

The specific kind of gel colour you're looking for is CTO, or "Colour Temperature Orange" which will convert sunlight into the same spectrum an incandescent light has. You can get "1/2 CTO" which has half the effect, "1/4 CTO" and so on, to make the effect less dramatic and better suited to your light source. (There are hundreds of gel colours, CTO is a good place to start.)

That said, anything vaguely orange coloured and translucent/transparent will help. Look for orange/yellow coloured cellophane film in the gift wrap section of your local dollar/party store. You can also just put a piece of clear tape (Scotch, or packing tape, e.g.) and colour over it with orange/yellow markers. Yes this works.
posted by seanmpuckett at 11:45 AM on October 8, 2018 [2 favorites]

I have an LED desk lamp that is too cool, and I just scribbled all over its bulb area with an orange sharpie. Did the trick for me.
posted by Anticipation Of A New Lover's Arrival, The at 11:52 AM on October 8, 2018 [1 favorite]

No gel will 'convert' colour. All a gel can do is remove certain colours and allow others to pass through. A gel can only make the light less blue, not more red or more yellow. When you strip out some of the blue light, the bulb will definitely appear dimmer, because there's less overall light. Having said that, the human eye is excellent at adapting to low light, so it's possible that a gel would work for you.
posted by pipeski at 2:19 PM on October 8, 2018

Also wanted to highlight that you might have two problems: Too cold color, and a low refresh rate.

If you look at the light and wave your hand between the light and your eyes - do you see a blur of fingers? Or do you see a series of images of your hand? If you see images, the refresh is probably tied to the mains and is 50 or 60Hz and is flickery. If that's the issue - then gels will not help - and you'll have to replace the LED and driver completely.
posted by kamelhoecker at 5:38 PM on October 8, 2018 [1 favorite]