The belief is widespread that the dark theme of the screen in electronic devices allows them to work out in autonomous mode longer. We checked whether this point of view is confirmed experimentally.
The fact that the use of a dark theme on the screen of a smartphone, tablet or laptop helps to delay it to recharge, write Media And Technobloggers. Some make this statement unconditionally, other Checkthat it is fair Not for everyone devices - it all depends on type of screen and regime use gadget.
Although the dark theme on which the application displays light letters on a dark background seems relative innovation (for example, for iOS it appeared in 2019, and for the desktop version of VKontakte - only in 2022), such a display of text on the screens of electronic devices actually "Older»The usual dark letters on a light background. Prior to the development of visual shells of operating systems, monitors with an electron-ray tube usually worked in a dark topic (for example, with green letters).
In modern gadgets Used Two types displays: LCD (liquid crystalline, LCD displays) and OLED (organic LED). LCD screens do not emit light on their own, but rely on a substrate that evenly highlights the display, so that in this case, switching from a bright topic on a dark one and vice versa does not affect energy consumption in any way. In OLED displays, LEDs emit light, so when the dark topic is turned on, pixels responsible for dark areas will not work and consume energy.
In 2018, Google told About the experiment, which was conducted with her Pixel smartphone, released two years earlier and equipped with an OLED screen. The engineers compared how the battery charge will be spent in a dark and bright topic with an open YouTube application. It turned out that the dark theme made it possible to save from 14% (at half of the maximum brightness) to 60% of the charge (with maximum brightness).
More modest results Received Researchers from the American University of Perdue. They compared the work of the Pixel 2, Moto Z3, Pixel 4 and Pixel 5 smartphones (all with OLED displays). For testing, the six most downloaded applications in Google Play: Google Maps, Google News, Google Phone, Google Calendar, YouTube and Calculator were selected. Each of them was included for 60 seconds, after which the researchers recorded the energy consumption of devices. The authors of the experiment also took into account that many users prefer to automatically configure brightness - its level selects the device independently depending on external illumination. It turned out that with the brightness of the screen of 30-50%, which the gadget usually uses in the room, the dark topic allows you to save only 3–9% of the charge compared to the bright. As the researchers specify, this percentage is so small that most users will not notice the difference in the duration of the smartphone. Therefore, scientists believe that to select the topic of the device, trying to preserve the charge, is not worth it. The only scenario in which the switching of the topic for this purpose will be, according to them, is justified is the use of a smartphone with automatic brightness adjustment on the street on a sunny day. In this case, the device will automatically set the highest level of brightness, and the transition to a dark topic, indeed, will save a tangible percentage of charge (39–47%).
Although both studies recorded some decrease in energy costs when using a dark topic, the smartphone was studied in them without taking into account user experience. This drawback was eliminated in its research Engineers BBC Research & Development. They planted ten volunteers at a distance of 50 cm from ten MacBook Pro laptops 2017 and asked to install a comfortable brightness on the devices to view the main page of the BBC Sounds. The streaming site allows you to use both a light and dark topic.
When using a dark topic, 80% of volunteers significantly increased the brightness of the screen. They continued to call it comfortable even with the gradual dimming of the premises where the test was held, although experiments conducted without the participation of people suggested that users would reduce the brightness of the display as the space was darkened. Such behavior, according to researchers, nullifies all the advantages of a dark topic in terms of maintaining the charge. They called this the effect of the rebound and Recommended Those who want to extend the battery life of the gadget, choose not a dark topic, but a lower brightness of the display.
"Checked" already Disassembled Another popular myth of the dark theme of the screen is as if it is more useful for vision than bright. It turned out that it provides insignificant advantages only to people with visual impairments caused by clouding of the optical media of the eye (for example, with cataracts). Otherwise, scientific experiments have not yet been able to prove the usefulness of a dark topic, so it is pointless to include it on the phone or tablet, motivating it with care of health.
Thus, a dark topic does not always help to maintain a charge of a phone or laptop. For devices with LCD displays, there will be no difference due to the principle of operation of such screens. In the case of OLED displays, the conservation of the charge will be significant only with prolonged use of a dark topic on the street on a sunny day on a device with automatic brightness adjustment. However, as some studies show, when the dark topic is turned on, users, regardless of external illumination, tend to increase the brightness of the screen, which nullifies all the advantages from the point of view of energy conservation.
Image on the cover: Photo by Jethro C.
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