Light Mode: Good or Bad?

A fun fact about me is that I use light mode on most applications. This has often come as a shock to people when dark mode has seemingly become the new standard for applications. Personally, I enjoy light themes. Something about it being plain and boring is nice and comforting, or something. Others really don’t like it when I send a screenshot and they see that the application or website I am using is in light mode. I actually used to use dark themes, but I went over to the light side. Why? Mostly just to annoy people. But in my debates with people over which is better, I wondered if there was actual evidence to one being better than the other. After all, there was some truth to the fact that light mode can appear brighter than dark mode. So I aim to explore this idea and see which theme is truly worth using.

While I don’t exactly have the time and resources to conduct a proper experiment to see how the theme of a system can impact a user, there has been existing research done on this topic. This article aims to compile multiple peer reviewed papers to come up with a concrete answer to the question. To properly understand some of the papers, some terms should be defined. Dark mode, or dark themes, are comprised of white colored text on a black or dark colored background. Light mode, or light themes, are the inverse. black or dark colored text on a white or light colored background.

Productivity is often claimed to be a selling point of dark mode. Many claim that dark mode may be easier to look at and thus better for longer working sessions. However, a study was done that disproves this. A study done with both users who prefer light and dark mode was done to see if light or dark mode had an advantage in productivity. Participants were tasked with writing phrases using a virtual keyboard. They had to use both light and dark mode while completing this task. The results showed that the difference between light mode and dark mode did not change the users WPM or error rate in any meaningful way. The researchers end up saying the choice is more-so “an expression of a user’s identity rather than a choice founded in ergonomic rationales” (Pedersen et al., 2020). To me, this does the best job of highlighting the fact theming is more so a matter of pure preference. While I think the methodology used may have not been the best way about testing this, it does prove that, at least in this particular case, how you choose to theme your software doesn’t really matter, at least in terms of productivity.

Another claim in favor of dark mode is that it is less disruptive to a user’s circadian rhythm, meaning using dark mode makes it easier to fall asleep. This already comes as dubious to me as a study by Duraccio et al. (2021) suggests that programs that reduce blue light exposure in order to help you sleep, such as the iPhone’s night shift feature, have little to no impact and that not using devices before bed gave the best outcomes. While reducing blue light is not the same as using dark mode, both have a similar effect. Traditional screen technology works by changing the amount of red, green, and blue light for each pixel. As such, dark mode would have less blue light as dark colors are characterized by the absence of light. However, a true black cannot be produced due to traditional screens using a large back light to provide light for multiple pixels. But as the research showed, this has virtually no effect on circadian rhythm. More interestingly is that for OLED screens, which can produce no light for black colors, dark mode has an advantage. This advantage is not in the lack of disruption of circadian rhythm, but rather in power consumption. Using a theme that has true blacks in it on an OLED screen can reduce power consumption up to 75% (Dong et al., 2009). Due to the lack of easy access to OLED screens this makes it a rather minor point in the argument of light versus dark mode.

I will concede that dark mode has a distinct advantage in a more niche area, augmented reality. A 2019 experiment tested the difference between light mode and dark mode for usage in augmented reality displays. The researchers had participants read text and take simple visual acuity tests on various different background conditions and lighting conditions with both light and dark mode. Participants would give feedback based on how easy or difficult it was to complete these tasks given the conditions among other things. Results showed that tasks were easier, quicker, and more accurate with dark mode as well as dark mode causing less visual fatigue. Interestingly enough, better light conditions also lead to an increase in performance (Kim et al., 2019). While this may seem as proof that dark mode is better than light mode, this research was done in a completely different context than the one most of us use on a daily basis. I think I can say with confidence that 99.99% of readers of this blog are reading on a standard desktop monitor and not through an augmented reality display like the research.

But the big key argument comes down to visual fatigue. Many claim that light mode is harder to look at and read content on. In a study done by Xie et al. (2021), tests were done to see if light or dark mode was more beneficial for reading content in a dark room. The results indicated that dark mode results in less visual fatigue when using screens. However, I think this ignores some possible causes of strain. Many studies have been done on computer vision syndrome, a phenomenon related to visual fatigue when using devices with screens. There are more factors than just using dark or light mode that can contribute to eye strain. A study found that “For example a dark background screens often require lower lights level so when other source of documents are also viewed at the same time additional reading lamp may be needed to prevent ocular strain” (Loh & Redd, 2008). Another study found that “The brightness has to be adjusted so that it is about the same as the surroundings” (Agarwal et al., 2012). Simply put, dark mode requires darker ambient light to be more comfortable, and the inverse is true for light mode. While these study agree with the research done by Xie et al., it also gives merit to the usage of light mode. Light mode is more appropriate for viewing content in brighter conditions.

Research seems to indicate that, except for a few niche exceptions, that there is advantage to using either light or dark mode. It is a preference that is purely up to the user, although it would have been nice to see some evidence pointing to one being better than the other. I still prefer the usage of light mode, as it forces me to keep a well lit environment, which is useful for other tasks than just using a computer.

Regardless of if you use light mode or not, I have to ask if you are using it in an appropriately lit environment. You only get one set of eyes so please take care of them.

Sources

Agarwal, S., Goel, D., & Sharma, A. (2012, December 24). Evaluation of the factors which contribute to the ocular complaints in computer users. Journal of clinical and diagnostic research : JCDR. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3592304/

Dong, M., Choi, Y.-S. K., & Zhong, L. (2009, August 1). Power-saving color transformation of mobile graphical user interfaces on OLED-based displays. Association of Computing Machinery. https://dl.acm.org/doi/10.1145/1594233.1594317

Duraccio, K. M., Zaugg, K. K., Blackburn, R. C., & Jensen, C. D. (2021). Does iphone night shift mitigate negative effects of smartphone use on sleep outcomes in emerging adults? Sleep Health, 7(4), 478–484. https://doi.org/10.1016/j.sleh.2021.03.005

Kim, K., Erickson, A., Lambert, A., Bruder, G., & Welch, G. (2019). Effects of dark mode on visual fatigue and acuity in optical see-through head-mounted displays. Symposium on Spatial User Interaction. https://doi.org/10.1145/3357251.3357584

Loh, K., & Redd, S. (2008, December 31). Understanding and preventing computer vision syndrome. Malaysian family physician : the official journal of the Academy of Family Physicians of Malaysia. Retrieved January 20, 2022, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4170366/

Pedersen, L. A., Einarsson, S. S., Rikheim, F. A., & Sandnes, F. E. (2020). User interfaces in dark mode during daytime – improved productivity or just cool-looking? Lecture Notes in Computer Science, 178–187. https://doi.org/10.1007/978-3-030-49282-3_13

Xie, X., Song, F., Liu, Y., Wang, S., & Yu, D. (2021, February 24). Study on the effects of display color mode and luminance contrast on visual fatigue. Digital Object Identifier System. https://doi.org/10.1109/ACCESS.2021.3061770