Should software developers jump the dark-mode bandwagon?

I have been wondering for some time now why there is so much fuss about the dark-mode among the software developers. I decided to dig more about it and share what I have found.

1. Introduction

Supporting dark-mode is far from being trivial if not designed from the beginning. As an example, Stack Overflow has invested significant effort (time and money) in adding dark mode and fixing most of the bugs.

Switching to dark-mode can incur a cost for developers as well. As an example, over the years I have noticed colleagues trying to convert to “dark-mode” programmers after switching teams. This typically happened in spite of significant adaptation strain.

The main source of inspiration for this article is this great LinkedIn post. It exhibits the perspective of a person suffering from astigmatism when using dark-mode user interfaces. While most of us do not suffer from astigmatism, I felt that most of the arguments there also apply to many software developers.

2. The pros of dark-mode

Dark-mode proponents provide multiple arguments to support why it is better that light-mode:

• too much light for the eye: monitors emit light that might lead to fatigue.
• reduce power consumption: OLED displays will typically drain less power (1.8% to 23.5%) and it is nice to use low-power consumers.
• “geek in a cave”: programmers tend to work in low light conditions, so dark-mode is closer brightness-wise to the environments.

Some of the counter-arguments for these points are the following:

• too much light can be compensated by dimming the screen brightness
• power consumption is true only for OLED display. Also, the nominal gain is very small compared to really serious consumers like A/C. If you are really into power-saving setting a moderate A/C temperature setting might lead to saving dozens of times more. From a more philosophical point of view, optimizing for power consumption for small consumers forces us to adapt to the technology instead of the desired option of adapting technology to our needs.
• “geek in a cave” preference for programmers is far from being true.

3. The pros of light-mode

• better in light environments
• better for reading (I will come to that later)
• closer to how our eyes evolved: Most of the world you are seeing is made of dark objects on a light background. And even if it is not particularly true for some, our eyes evolved for millions of years is such environments, and optimizing for dark-mode requires a lot of time.

I could not find any counter-arguments for these (most sources concentrate on pros and cons of the dark-mode).

4. Getting more technical

I have provided very general information and now I will focus on the specific case of software developers. What makes them special is that they spend a significant fraction of their life coding.

Since coding is mostly reading, it is important to understand the pro and cons arguments for dark-mode / light-mode when considering reading, not other types of activities involving staring at a screen.

As informed decisions are becoming more and more fashionable, I believe that also switching to dark mode should be analyzed more for a fact-based perspective.

Happily, there are some recent studies and articles that provide a great insight into dark-mode effects on reading. Here is some highlight from a NN group article:

(..) light mode won across all dimensions: irrespective of age, the positive contrast polarity was better for both visual-acuity tasks and for proofreading tasks.

although light mode was better for older adults, too, they did not benefit from it as much as younger adults, at least in the visual-acuity task.

the smaller the font, the better it is for users to see the text in light mode.

during daytime, there was no significant effect of contrast polarity, but during nighttime, light mode led to better performance than dark mode. Moreover, during nighttime it was much harder for people to read small-font text in dark mode than in light mode.

The study above also showed that we are poor judges of how well we are doing evaluating ourselves:

even though their performance was better in the light mode, participants in the study did not report any difference in their perception of text readability (e.g., their ability to focus on text) in light versus dark mode

However, there is a cost that comes with long-term usage of light-mode:

(..)study published in Nature Research’s Scientific Reports in 2018 suggests that sustained exposure to light-mode may be associated with myopia

Another interesting resource is the dark side of the dark mode which starts from Apple’s marketing announcement of dark mode and dives in most ramifications of various dark-mode aspects. It is a lengthy article, but with a very nice and short conclusion:

Use it [the dark mode] if you wish, but know that it’s a productivity hit for most people most of the time.

5. Conclusion

I am fully aware that using dark-mode or light-mode is a matter of taste these arguments will not convince to switch sides for many.

However, if you are more of a fact-based person rather than a faith-based one, this might help you decide which display mode is better for you.