Protect Yourself from Blue Light with Digital Color Filters

Originally published at: Protect Yourself from Blue Light with Digital Color Filters - TidBITS

Blue light emitted from screens has been linked to a number of health issues. Here are a couple of ways you can reduce or block it on your Mac, iPhone, and iPad.

What is wrong with using f.lux to change the color of a display?

I have had headaches for a large part of my life. They can have so many reasons:

  • wrong glasses
  • not enough hairclips
  • hair to heavy
  • mattress not hard enough
  • sitting wrong in the chair
  • desk too high or not high enough

And so on.

You can help your eyes with eye training. See “Improve Your Eyesight Naturally” at Amazon.

An important part for headaches is getting enough magnesium with “magnesium oil”.

I appreciate that you touched on the research and science (studies) as being unsettled, even though you write that it’s trending more likely to be a real thing. In recent years, products, like eyeglass lens coatings with blue light filtering for example, have been heavily marketed so I’ve tried to check on the science a couple times myself. And a few years ago, I asked my retinologist for his opinion. He acted like I had asked him about his political affiliation and he gave no useful answer. Discouraging. Prices dropped so my regular glasses now have premium (top of the line) blue light filtering. So do I still need to set up my Mac, iPad, and iPhone as you carefully explained? (Thank you!) Actually, I do for sure for my iPad and iPhone because I often use these without wearing glasses (my very close vision is better without glasses).

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Josh: Quick question here: You describe in detail, how best to mitigate blue-light emissions from Apple devices. With respect to blue-light emissions, what makes Kindle different than Apple devices? In your article, you say, you’d rather use Kindle at night, just before bedtime

I’m much better off avoiding my iPhone entirely before bed and instead reading on my Kindle.


Nothing, but as I state in the article, it’s hard to control manually. Plus, you can perform my method without installing anything extra. I’ve done some of the eye training exercises, but I should get the book and get more serious about it. I agree on magnesium and take magnesium chloride and magnesium glycinate daily.

Yes, I would, for the reason you outline. Also, extra protection won’t hurt. I’ve actually heard that it’s bad to wear blue light-blocking lenses in the sun but I have nothing to back that up with. I actually have some blue-light sunglasses that fit over my prescription glasses, but I don’t wear them often because they make me look goofy.

My understanding is that the Kindle Paperwhite’s lights emit some blue light, but not as much as an iPhone. The screen also isn’t as bright. All I know is that I fall asleep much faster reading my Kindle than if I’m reading on my iPhone, and I seem to fall asleep even faster if I wear my goofy blue light glasses mentioned above.

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Amazon Kindles don’t have backlights, they use E Ink, a reflective, not emissive display (LCDs and OLEDs are emissive). The Kindle Paperwhites and other models with LEDs have them arranged around the edges, casting light onto the E Ink so it’s visible in the dark. They use “white” LEDs that include blue wavelengths but you can turn down their brightness or turn them off and read with whatever light you want.

The fifth edition Kindle Paperwhite released in October (and the third Kindle Oasis) does allow you to adjust the color temperature of the LEDs, I assume allowing you to reduce the amount of blue in their light.

Yes, you’re correct. It’s not a backlight so much as sidelights. I don’t have the latest Kindle, but knowing that you can adjust the color temperature might tempt me to buy one the next time it’s on sale.

Let’s not forget the other devices in homes, like appliances, clocks, and accessories that cast a obnoxious bright blue light … like at night. A mask film, sharpie or other way to dim/mute that blue cast… its unnatural. It might be unlike the more time-consuming, harsh, unhealthy affect to some with migraines and such that use displays all day. But if you awake late at night, some accessories (OWC drives, Dlink switches, USB hubs…) light up a room, hall or numerous areas that you might not need turn a light on… same with car instrument displays and interiors.
Last month, I was made aware of the accessibility issues to many with the colour temp of displays. I know I am affected by the frequency of GM motors rear light LEDs on cars (try this, turn head/eyes fast to scan left and right…with GM SUV infront of you…its painful and noticeable). So lighting can affect many with painful results.

I’ve been using Night Shift with default settings on my mobile devices for years. I have found Philips Hue White Ambiance bulbs (I don’t need a disco party) and Apples HomeKit Adaptive Lighting, is quite nice. It’s very much Night Shift for your home lighting. Merely turning it on is a no-brainer. I noticed an overall level of comfort as a result and I set 3 scene brightness levels. I run the lights at 30% in the morning and evening. I added the Lutron Aurora that locks the wall switch to the on position and gives you a push-click ON/OFF and a dimmer dial which controls the Hue bulbs if I feel the need to override my brightness automation

Several years ago I invested in a pair of orange safety goggles, designed speifically to exclude wavelengths from blue up (for people using industrial lasers). I’ve tested them and found that they do, indeed, exclude all blue and higher light. I wear them in the evenings. Whether they truly help my sleep, I don’t know (I use a combination of tools), but the scientific basis is sound. All light stimulates alertness. Brighter light is stronger. Higher-energy light is stronger. So blue (indigo, violet) light has the greatest effect.
I wear UVEX brand.
I’ve read that Raymond Teller (of Penn and Teller) wears orange goggles too, and swears by their effectiveness.

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I find the best way to read on my iPhone (so as not to disturb my bedmate) is to have the red filter to 100% and have the book (in the books app) set to back page/white text, this makes the text completely red. If I am awake in the night, I can read without disturbing anyone, plus the red light doesn’t disrupt my night vision.


This is all moot and a waste of time for anybody that profiles their monitor for color balance and uses picture editing software to view accurate colors. But thanks anyway.


Very useful for skygazers too. Although most planetarium apps have the red filter built-in, it’s handy to have it available system-wide.

Have adjusted the settings on my iPhone X as suggested and will try it out and report back. Many thanks!

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The article says “Night Shift, introduced in iOS 9.3 and macOS 10.12.4 Sierra…”. I am on 10.13.6 and there is no Night Shift in the Displays Preference.

Night Shift also has hardware requirements, it won’t work if the Mac is not new enough and it won’t work if the display won’t support it. Use Night Shift on your Mac. It does work with more displays than those listed in the support article, it works with my 2020 HP monitor using DisplayPort.


A couple of pointers for this system that I’ve developed recently:

  1. The red color filter can make many onscreen elements hard to see, especially if they’re blue, red or orange. If you turn down the Intensity slider a few notches you still block most blue light while making the filter much more usable, which means you’re more likely to keep it on.

  2. You can automatically turn this on with a Personal Automation. Open Shortcuts, tap Automation, tap the +, and choose Create Personal Automation. Choose Time of Day, Sunset, and then adjust the time to your preference. After tapping Add Action, search for “color filter” and choose Set Color Filter. You can also use the same automation to turn down brightness and turn on Dark Mode.