A system-wide night theme would let iOS look and feel great throughout the day, and be a huge accessibility benefit.
iOS 10 has shipped and while it's always possible we'll get an iOS 10.1, 10.2, or 10.3 surprise, Apple is already getting ready to roll on iOS 11. That means there's no better time than now to get with our wish-lists, and one of mine remains a system-wide dark appearance. Apple TV got it with tvOS 10, so why not iPhone and iPad?
Rewind: When iOS 7 shipped in 2013, it did so with a redesign that not only moved skeuomorphism away from rich textures and towards rich physical interactions, it also painted everything bright white.
It makes the iPhone and iPad look clean and spacious, which is fine for everyday use. When it comes to low-light situations, though — like the home theater or the bedroom — that intensity is enough to get you yelled at or hit with a pillow. When it comes to accessibility, it's also enough to contribute toward eyestrain.
State of the night
Because there's no system-wide dark mode in iOS, some people resort to using Invert Colors — part of Apple's existing accessibility support — which does turn the interface from white to black … but also turns blue to orange, green to purple, and every color to its opposite. Including your wallpaper, your photographs, your everything.
It's not usable for most people, and certainly not every day.
Apple's iBooks already has a proper dark mode: You can manually switch it on or set it to turn on automatically at night. Rather than invert colors, it sets them appropriately for low-light conditions. It makes the white background black, the black text light gray, and blue and green tint colors the right shades of gray. Importantly, it leaves pictures, photos, and other graphics as they were, so they maintain the proper colors.
Maps has gone dark as well, which helps when navigating at night.
Some App Store apps include their own dark themes as well. In Fantastical, you can toggle a light mode on in the app's settings. In Tweetbot, a Twitter app, you can swipe down with two fingers to switch between light and dark modes.
Many apps don't provide the option, though, and even those that do vary in their implementations. That leads to an inconsistent experience.
Apple Watch, by contrast, has a dark mode as its only mode. That's because it uses an OLED display. Unlike the LED of iPhone and iPad backlight, which is either all on or all off, OLED can light up only the pixels it needs. That makes black more power efficient than white, which is especially important on devices with tiny batteries like watches.
With iOS 9.3, Apple added Night Shift to iPhone and iPad. It's a technology that gradually, over the course of the day, changes the display from cooler (blue) toward warmer (yellow) along the color spectrum. You can choose to have it happen naturally from sundown to sunrise, between any pre-set times, or you can flip the switch manually. The idea is that the warmer cast preserves melatonin build-up and suppresses histamine, which is ultimately less disruptive to sleep patterns.
That's all terrific, and it absolutely enhances the overall iPhone and iPad experience. But it doesn't address what a dark mode would — it changes the color cast of the display but doesn't do anything to radically inverse its brightness.
A yellower light is still a light.
On the NightKit
When an environment is dark, any light will stand out all the more brightly. It becomes a beacon. It becomes neon. That's where a dark mode would come in.
If Apple could provide a dark mode for all its apps, it would go a long way toward making the iPhone more usable in the dark. If Apple could take it a step further, though, and provide a "NightKit" framework for its standard UIKit interface system, then any App Store app could tie into it as well.
That way customers could choose Dark Mode once in Settings and have it automatically enabled everywhere, in every app that supports it, all at once. Like Night Shift, it could live in Settings > Display and Brightness, and be toggled on or off from Command Center at any time.
For developers, a framework could conceivably let them tweak parameters and set colors so that their app's interface looks exactly the way the developer wants in either light or dark modes.
To nail a dark mode system-wide, and to make it work for developers as well, is no doubt a monumental task. In theory, something like CSS could be a model for a full-on theming engine. In practice, a legion of devils lurk in the implementation details.
Either way, every time I turn on my iPhone in the dark and my eyes squint for a moment as the world goes suddenly white, I'm reminded how the lack of a dark mode remains a problem. And solving those kinds of problems is what Apple does. Hopefully by iOS 11?
What's on your wish list?
What do you want to see when it comes to iOS 11 design? Let me know!
I've filed this feature request with Apple. It can be found at rdar://19760524 (closed as a dupe of rdar://11786790). Do you want a system-wide night theme? Let me know!