Certain types of modern displays use less power when displaying a black or dark background, including the technology used in the Apple Watch. It’s all thanks to the wonders of OLED and self-emissive display technology.
Why Do Dark Themes Use Less Power?
Apple opted for OLED display technology for the Apple Watch from the very first model. Unlike traditional LED-lit LCD screens, OLED is a self-emissive technology. That means there’s no need for a backlight at all because each pixel generates its own light.
This enables for pixel-level light control and perfect blacks. To display pure black, pixels are simply turned off. This consumes no power and makes the rest of the watch face stand out against the deep black background.
Watch faces that use mostly dark or black elements use less power than a watch face with lots of bright white or colorful elements. The brighter a pixel, the more power it consumes. If you can replace a bright solid-colored background with a black one, the display will use less power because more pixels are in the “off” state.
It’s hard to say by how much this will affect your battery usage, so the best way to find out is to try it for yourself. If your Apple Watch is frequently running out of battery, a darker background might make a little bit of difference. It’s worth a try. If you have solid battery life, you might not notice the difference.
Regular LCD-lit displays don’t turn off the backlight when displaying black or dark colors. Instead, they “block” the backlight with varying degrees of success. Not only does this require the use of an always-on backlight, but it also makes blacks look washed out.
Some iPhones Can Benefit, Too
It’s not only your Apple Watch that might see a battery boost that self-emissive display technology brings. Some of the higher-end iPhones from the last few years also have OLED displays.
If you have an iPhone X, iPhone XS or XS Max, iPhone 11 Pro or Pro Max, or any iPhone 12 model (Pro or otherwise), then your device uses an OLED display. If you want to squeeze out some more battery life from your iPhone, you might want to set a dark background and enable dark mode.
Try Switching to a Dark Background Today
If you’re experiencing less-than-ideal battery life on your Apple Watch, then a dark background could help, particularly if you have an Apple Watch with an always-on display like a Series 5 or Series 6.