The main purpose of the night’s themes is to provide a comfortable interaction with a smartphone in the dark. The lack of lighting night theme makes the interface of the operating system and all installed apps dark, making the white light hits the eyes, and doesn’t force you to reduce brightness to minimum to see anything on the screen becomes very problematic. However, there are those who are willing to enjoy the night theme not only at night but during the day, finding it not only comfortable but also energy efficient.

The authors of the YouTube channel PhoneBuff has conducted independent testing night themes to see whether in fact it reduces the power consumption. This was taken XS iPhone with installed iOS 13, which has consistently experienced with a light and night theme when screen brightness of 200 nits.

And that experiment went as objective as possible, testing was assigned to the robot that consistently perform the identical range of tasks that are typically performed on smart phones, from correspondence in iMessage and navigation through Apple Maps to watching a video on YouTube.

As iPhone is discharged with the night theme

As discharged iPhone with night theme (blue scale) and without (orange scale)

The result was evident almost immediately, however, really became noticeable only in the second hour of usage, when the iPhone XS with light theme spent 5% more battery life. After four hours the gap had increased even more, reaching 15% in favor of the unit with a night theme. At the beginning of the seventh hour of the testing apparatus with the night theme of dead to 43%, while his opponent is under 20%. The experiment ended in the complete discharge of the sample with the light theme, which happened on the 7 hour 33 minute. However, at this point, the instance with the night theme had a 30% charge.

This experiment has been very significant in demonstrating that the night theme is really able to save some battery life, and quite bad. In the end, very few people voluntarily give up a thirty percent increase autonomy. However, to achieve this effect will be possible only on iPhone with AMOLED screens. This is due to the technology of their production. In contrast to IPS displays, which have a separate backlight, AMOLED consist of a large number of individual pixels light up independently from each other. So when you want to display black, it simply extinguishes the LEDs without consuming energy at all.

What’s wrong with AMOLED displays

Looks like a burn pixel on AMOLED screen iPhone X

Unfortunately, AMOLED screens, along with the above-described advantage, carry a very serious drawback. Because of the peculiarities of the device organic panels suffer from the so-called memory effect, which is also referred to as burnout. Display simply remembers the static image that displays on a regular basis (e.g. desktop Wallpaper) and then superimposes it over the main image. Looks like this effect is, frankly, so-so.