What is?
It’s been for a while now that we see smartphones, applications and recently also OS introducing the ability to set their interface to dark Mode or Theme
But why is it that?
Apart from a pleasing look for some people, it also comes with some advantages and disadvantage.
The first advantage we could think of is the fact that having the screen to show its content with a reverse colour meaning what was white is now black and vice-versa, it implies that we are using less power extending, therefore, the battery life of our devices.
Although this is true, we should distinguish two of the most commons display types used in today’s consumer devices:
- LCD or Liquid Crystal Display,
- OLED or Organic Light-Emitting Diodes
And to highlight that the energetic benefit is mainly related to the OLED displays.
The reason is due to the technology behind these displays, which is beyond the scope of this post.
The second advantage is related to the fact that for users who use computers or other mobile devices for an extended period of times a dark screen results in a lower chance of eyes strain and other health-related factors like a headache.
However, for those who read a lot, the dark mode or precisely white font on a black background may affect negatively.
The main reason for it is the high contrast plus the fact that the white letters on black are not as sharp as a black letter on white, but these are casting some halo around their contour.
The other reason is related to the way our eyes are putting images on focus and understanding why is that we need to understand how our eyes are achieving so with some analogy to cameras.
It is the non-straight forward disadvantage mentioned earlier.
The irises are regulating the amount of light getting into the eyes by contracting or relaxing.
Similarly to camera lenses where a diaphragm is resized to get more or less light to the image sensor, for those who have some experience with photography knows that resizing the diaphragm or (a photographer would say) changing the aperture affects the depth of field.
It is the non-straight forward disadvantage mentioned earlier.
The irises are regulating the amount of light getting into the eyes by contracting or relaxing.
Similarly to camera lenses where a diaphragm is resized to get more or less light to the image sensor, for those who have some experience with photography knows that resizing the diaphragm or (a photographer would say) changing the aperture affects the depth of field.
The Depth of Field or DoF for short represents the amount of stuff that is in focus.
Going back to our eyes, we know that when is light (in the day) our iris is contracted to minimise the amount of light getting to the retina while when is dark the iris is relaxing or getting fully open to capture as much light as possible.
In photography, when you increase the aperture (stepping down the f-number), the depth of field gets shallower leaving anything out of the focal point out of focus.
The same happens to our view.
When we read on a dark background because of the lower light getting into our eyes, the iris are relaxed blurring out the rest of the page. Although we do not realise, our brain perceives it, and can make us quite tired if we read for an extended period under the same condition.
Conclusion
In conclusion, the dark mode can be pleasing, extend the battery life and be environmentally friendly; however, we should consider which applications we want to switch to dark mode and which instead is better to keep in standard light mode.
Fortunately, many applications let you customise the theme (or mode) of the interface and the canvas (the working area) independently and their namely dark mode usually turns into some shade of grey rather than black which is more acceptable to our eyes.