The Dark Side of Dark Mode and Night Shift
Adam Engst (tweet, Hacker News):
Unfortunately, Apple’s marketing claims about Dark Mode’s benefits fly in the face of the science of human visual perception. Except in extraordinary situations, Dark Mode is not easy on the eyes, in any way. The human eyes and brain prefer dark-on-light, and reversing that forces them to work harder to read text, parse controls, and comprehend what you’re seeing.
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In the scientific literature, black on white is called “positive polarity,” whereas white on black is called “negative polarity.” Numerous studies over decades of research have found that positive polarity displays provide improved performance in a variety of areas.
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When there’s a mismatch between the two—the screen is too dim outside or too bright inside—it’s hard to look at. That’s why Apple implemented automatic brightness control in iOS (find it in Settings > General > Accessibility > Display Accommodations) to reduce the screen brightness when you’re reading in a dark bedroom and increase it when you’re trying to take a picture on a sunny day.
I haven’t personally found any use for Dark Mode on my Mac. I don’t like the way it looks, and it feels like it slows me down. I have always preferred light text on a dark background for code, though. My sense is that this is not because I like light-on-dark better than dark-on-light for the primary text, but rather because most of the other colors work better on a dark background. With multi-color themes, the secondary colors tend to be easier to see on a dark background.
I don’t like how Dark Mode looks on iOS, either, except that I’ve always preferred Tweetbot in dark. I also like to run OmniFocus in dark so that the screen isn’t so bright if I’m making a note at night. Automatic brightness control just doesn’t cut it.
I continue to like Night Shift.
Giving on up dark mode.
Don’t like.
I get double vision due to my eye condition on most text and in almost all dark mode implementations it’s far more pronounced.
John Gruber found that Dark Mode helps with his eye condition.
These features are designed to change the temperature and color of your display based on what time of day it is. New research suggests, however, that features designed to reduce blue light before bedtime might not be as effective as initially thought.
Previously:
Update (2020-06-05): Isaiah Carew:
i’ve been using the pseudo-dark mode in the accessibility controls for years. on the mac too.
i don’t care what the studies say, it is one of the few things that has made a noticeable difference in my dyslexia.
dyslexic fonts and retina monitors are pretty great too.
Update (2020-11-27): Kev Quirk (via Greg Hurrell, Hacker News):
According to the reading I’ve done, dark mode isn’t easier to read and it doesn’t prevent eye strain. However, in very specific circumstances it can improve battery life.
I’m sure there are people out there who genuinely need dark mode for a specific health condition. For that reason, there will continue to be a dark mode on this site.
But if you’re like me, and just prefer dark mode, you may be making things more difficult for yourself and actually damaging your eyes in the long run.
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I mostly appreciate dark mode on my phone, but on the desktop have never liked it. The older I get, the more I find that I just see everything better with light backgrounds. I think it has something to do with the amount of light that actually hits and triggers the receptors in the eye decreasing as one ages.
In the 1970s, I worked on vector graphic CRT's that displayed white text on black backgrounds. At least they let me increase the text size be an easily readable. Back in about 1980, I started working on a VT100 terminal. I realized I could show black text on white background, and I've never looked back.
"I have always preferred light text on a dark background for code, though. My sense is that this is not because I like light-on-dark better than dark-on-light for the primary text, but rather because most of the other colors work better on a dark background. With multi-color themes, the secondary colors tend to be easier to see on a dark background."
I think that's a key insight! I strongly dislike dark mode in general, but color-coded syntax coding works very nicely in dark mode.
I think a lot of it depends on your preferred ambient lighting.
In an office environment, where the room is brightly lit, a light background works best. Your eyes don't do nearly as much adjusting when shifting between the screen and everything else you look at.
But when working in a dark room - as seems to be common for gamers, hackers and a not-insignificant number of photo/video editors - then the opposite becomes true. A dark background will keep your eyes from massive adjustments when you shift between the screen and the rest of the room.
As for Terminal-based applications, it appears that the default colors for quite a lot of popular apps/shells were defined back in the day of physical terminals (which typically had black backgrounds) or DOS-based terminal emulators (which also defaulted to black backgrounds). So the chosen colors were ones that look good against a black background.
But when those apps are run in a terminal with a white background, many of those colors (e.g. cyan and yellow) end up almost unreadable. In some cases, you can configure your terminal and apps for alternate color palettes, but in some cases you're just out of luck.
Dark mode's massively easier to see *on a screen*. Most research is about paper or other passive displays, where the white is not light-emitting, but reflective, and you don't generally read paper under direct sunlight or a UV lamp. With a screen, where light pixels are shining bright LCD light into your eyes, you want as few of those as possible.
I don't understand/mostly fear daywalkers who like a tiny sun shining into their face at all times, but I'll continue sitting in my dark room with dark screen and nice neon colors. On websites like this, or Gruber's grey-on-grey anti-theme, I use my Monochrome bookmarklets https://mdhughes.tech/tools/bookmarklets/ to make everything nice and dark. In my editors of choice, I pick a dark mode like Hackerman https://github.com/mr-ubik/atom-hackerman-syntax