Dark Mode as a graphical interface option has become an increasingly common feature. More than a fashion, the interest in design with dark modes and more intense contrasts also have technical support: the dark graphics interface results in battery savings of up to 60% in extended sessions of use. However, for this to happen, the user needs a smartphone equipped with an OLED-type screen. Also known as dark mode, the feature is present in Android 10, iOS 13 and apps like Instagram.
The difference between LCD and OLED
Using a dark theme with black backgrounds instead of white and other lighter colors ends up resulting in power savings only on OLED displays (also included are variants of this technology, such as AMOLED, Super AMOLED and Dynamic AMOLED from Samsung).
This is because of the nature of this type of display. When an OLED screen displays a black image, the pixels that form the space in which black is being displayed on the screen are effectively turned off. So if the graphical interface of the system or app you use is predominantly dark, the battery consumption of the phone drops dramatically, as most of the screen is turned off in effect.
LCD screens, on the other hand, do not allow portions of the display to be turned off according to the prevailing color. In LCD screens (usually IPS type in cell phones, such as Zenfone 6 and iPhone 11) no matter the color of the pixels: the entire display is always on even in dark mode, which means that the power consumption ends up not being affected by these devices.
How big is this saving?
The PhoneBuff channel on YouTube has put the theory to test the amount of battery that is saved when using dark interfaces on mobile phone with an OLED screen. In the test, the site used a robot that simulated the normal use of an iPhone XS Max with dark mode enabled in one and disabled in the other.
The results were very expressive. In two hours of use, the battery of the dark-themed iPhone was 88%, while the light-themed phone had already dropped to 83%. In four hours of testing, the difference in power consumption becomes more significant: the XS Max with dark mode features 72% against 57% of the device running with the iOS light interface. At the end of the experiment, the light-screen iPhone XS Max completely drained the battery after 7 hours and 33 minutes, when the dark-mode iPhone still had a 30% charge.
In addition to the channel-driven test, there are also official Google estimates that revealed that the combination of OLED and dark interfaces could result in power savings of 63%. One effect of these results is the new Android 10 promotes support for triggering dark themes through the operating system settings.
Dark mode in systems and apps
As the industry has progressively replaced LCD screens with OLEDs, the trend is for dark interfaces in systems and apps to become more frequent. In addition to systems that offer the possibility of using an interface with darker tones, there is also support for new features via apps: Instagram already offers the option in its latest versions and it is also expected that the new features will arrive at WhatsApp soon.