Dark Mode Saves Your Phone and Your Eyes

Recent studies have found that dark mode has risen in popularity and that it can benefit the phone as well.

Dark mode is a setting on many phones, most notably the newest Android and iOS devices. In the words of Linus Tech Tips, “Night mode is a color scheme or theme that can be applied to either a specific application or in some cases even system wide.” 

It makes the phone apply a darker color scheme like having white text on a black background. 

The feature is mostly aesthetic but has been found to have other practical effects.

Dark mode is not the same as “blue light filter” or “ night shift.” Those work by warming the colors away from the blue end of the light spectrum to reduce the amount of blue light is emitted but have little effect on the color scheme displayed.

Tech reviewer Lew Later reviewed a story pertaining to the battery life of an iPhone using dark mode versus light mode. 

“When the phone is in dark mode it was capable of going through the same set of tests but having 30% battery life left when the other light mode device died.” This test was on an iPhone running iOS 13. 

Later adds, “it’s going to be a device to device basis but it’s kind of exciting because now you have this method keep your phone at a 30 percent improvement in your battery just by using dark mode.”

Battery is not the only feature improved by dark mode. King Tech High Information Technology teacher Emily DaLuz confirms that using dark mode will reduce the amount of blue light that is emitted by your phone. 

Blue light isn’t necessarily bad but it is known to stimulate the brain when it is supposed to be resting. In addition to the blue light filter, dark mode can help make the screen easier to look at.

Of course if the goal is to save power and reduce blue light, power saving mode and blue light filter will be much more effective but dark mode provides an interesting side effect of increasing both modes just by changing the color scheme.

Dark mode is primarily a color scheme and using it is a personal preference. South High School Senior Nolan Baird, said “I do indeed use the dark mode. I use it because it is less of a strain on my eyes and looks cool.” 

The power saving also works back to the Galaxy S8. “When I first turned it on I did notice a small increase [in battery saving].”

Alternatively, Dimond Senior Josh Bell on his iPhone XR said, “I use it sometimes at night I believe but mostly I don’t use it. I don’t use dark mode, I use the night shift instead because I don’t like the dark mode theme.”
There’s more than one way to ease your eyes and battery with varying levels of results depending on the phone and user.

Later said that dark mode should have come sooner. 

“It’s kind of strange that it took so long dark mode. It just makes a lot of sense in a lot of ways. Yet we’ve had these devices for a decade and dark mode is only becoming ubiquitous now” he said in a podcast.

There is one caveat in using dark mode for power saving. It only works on OLED displays. Samsung has been using OLED since about 2013 so chances are most of those are running OLED. Apple started using OLED in 2017 with the iPhone X. Any later iPhones Are probably using an LCD display. 

LCD stands for Liquid Crystal Display. It works by shining a backlight through a layer of liquid crystal to make the color the display needs. 

DaLuz  added, “You can tell these monitors apart because you run your finger along the screen and providing a little pressure, you can actually see the liquid in the monitor move.” 

It is most commonly used in PC monitors due to its resilience to “burn in,” an effect where an image can become permanently stuck on the display when it is displayed for too long.

OLED stands for Organic Light Emitting Diode. It is more comparable to having thousands of tiny LED lights flashing to create the image only OLED uses more organic pieces to create each pixel. 

DaLuz said, “OLEDs are preferable over LEDs and LCDs because they are better on the eyes. OLEDs are more [power] efficient , offer wider angle displays, and have faster response times… OLED is going to emit way less blue light than LEDs or LCDs.”

Monitors work by giving each pixel a red, green, blue value. The colors will blend together to create whatever color is needed in that pixel and when all three are at full they produce white light. 

This allows for greater color contrast over LCD because OLED can simply turn off black pixels to create a true black but LCD backlight will still shine through.

Blue light is reduced in night shift because the pixels turn down the blue value which creates the warmer colors. The lack of the blue diode means that less blue light will be emitted and the greater red and green values mix together to make a more yellow color.

This method of using individual diodes instead of a backlight is the reason OLED saves power using dark mode. Given that dark mode makes most of the screen black most of the time, the pixels that are in the black area simply turn off and do not require power. In light mode, all the pixels have to be turned on and, given the background is usually white, all pixels have to be on at full power.