It’s OK to Like Light Mode – Project Runspace

Gatekeeping is one of the worst ills of the technology world. Someone with no authority finds an arbitrary reason to tell you that you’re not a “real” something, or they use it to try to shame you. For reasons that I certainly can’t explain, many people in tech love jumping on the bandwagon and gatekeeping whenever possible. The latest “big thing” is dark mode. Not only is it the foundation for enormous amounts of shaming and gatekeeping, it’s also been a great excuse for software houses to avoid real problems. Software buggy? Divert resources to building dark mode! Customers unhappy with software behavior? Divert resources to building dark mode! And so on. Well, if you don’t like dark mode, that’s OK. If they don’t like that you don’t like dark mode, that’s OK too. If you think that developers should spend time on actual problems instead of focusing on dark mode, that’s definitely OK.

The Science of Dark Mode

If you look, you will find tons of studies that say that dark mode beats light mode. If you look closer, you’ll find that the methodology of those studies was subjectively asking people which one they like better. Aesthetically, most people prefer dark mode. If that speaks to you, great! No one has the right to dictate your taste. I also suppose that when switching from a light mode screen to a dark mode screen, everyone’s initial reaction is positive. That doesn’t make dark mode scientifically superior.

Claims about dark mode’s superiority usually talk about eye strain and such. Some people claim that they experienced a reduction in eye strain since making the switch to darkness. In fairness, let’s accept the possibility that this might be true for some people. Biology is weird and few rules apply equally to everyone. However, let’s also understand that scientifically, most people will not enjoy a physical benefit from dark mode.

I looked at the surface level science first. Objective studies unequivocally say that light mode works better.

During my research, I kept encountering mentions that we don’t blink as much when looking at brightened screens as we do when looking at the natural world, and that seems to be the major reason your eyes hurt when looking at a computer all day. Back in the 2000s, they told us to periodically look away from the screen. It seems like this we should still follow this rule first.

All that said, I didn’t like just going with the science that agreed with me. If we account for the human propensity to join groups and shun outsiders, it still seems like dark mode has an overwhelmingly large following. So, I went further than the surface level.

The Evidence of Your Eyes (and Camera)

Have you ever noticed how many tech people are also into amateur photography? This is one of the reasons that the popularity of dark mode among techies baffles me. If you have ever attempted to take a picture of something on a dark background, you should already know what I’m talking about. When the majority of a scene is dark, taking a clear picture can become frustrating. That happens because you need a minimum amount of light to see anything. The less light coming in, the more your pupils must dilate in order to gather enough photons to detect objects (the camera analog is aperture). However, the wider the pupil/aperture, the worse the focus. With a camera, we can offset this problem somewhat by adjusting the shutter speed. For photographers, this means that movement by the camera or subject will still result in a blurry picture. Our eyes function more like motion cameras than still cameras, so we don’t really have an option. We just ask our brains to figure it out. I’m not an eye or brain doctor, but even I realize that this means that dark mode requires more image processing power from our brains.

The Role of Color in Dark/Light Mode Schemes

I jumped into and then out of dark mode long before it became a worldwide fad. Like many, I toyed with taking the available dark mode schemes and trying to adjust them more to my personal liking. I quickly discovered that contrast made an enormous difference (science proved it). While I know that the linked study and my own tinkering uncovered the necessity of contrast, I do not know why our eyes/brains need it. I could make some guesses, I suppose, but I’m no scientist. The science says that we need contrast.

So, understanding that contrast matters, now think about how that plays out realistically. Consider the hex color scale used by modern screens. The value for the most vivid red is #FF0000. That’s FFFF, or 65535, shades of difference between red and white, but only FF, or 255, shade differences from black. You get the same math for green and blue. But, it doesn’t seem like it translates well into reality. Consider this test:

I suppose everyone might see this differently. For me, the red is more or less equivalent on either background although I read it slightly better on white, the green pops very nicely against the black background, but I can’t read the blue on black at all. To make it more close to how you would encounter it in real life, I tried both tests on an entire screen of white and then an entire screen of black. That didn’t change anything for me. I read a lot of things on color theory to try to figure this out, and let’s just say that I don’t understand. So, while contrast makes a difference, it seems that “contrast” goes beyond simple math. For comparison, I inverted the above colors and got the following:

I don’t know about you, but it seems like I can make out the magenta text about as well on both backgrounds, but the cyan and yellow show up much more clearly on black. That tracks with what I discovered before popular opinion and science got in on the game: duller, more pastel-like colors look better on black. I don’t like those kinds of colors, especially yellow. That’s what kept me in light mode long before it became a thing that people like to argue about.

The Role of the Backlight in Dark/Light Mode

One pro-dark mode argument was that it uses and emits less energy. That should mean that fewer photons strike your eyes, so less energy burned and less energy to process. In most cases, that idea doesn’t seem to work out. The backlight of your device uses more energy than anything else in the display. Even when all the pixels are black, the screen isn’t really black. You also still have to dilate your eyes so that you can see a predominantly dark screen, so you still get a lot of ambient photons from other sources. As display technology improves, this might become better. Today’s screens definitely emit less light than old CRTs. However, unless we can reach a place where we do not need backlights at all, this won’t make a real difference.

The Summary of Everything Above

From reading all the scientific articles, I ended up with these conclusions:

You need to blink more
Black text on a white background is easier on your brain than white text on a black background
When colors become involved, contrast matters most
Light mode means smaller pupils which means easier focus

Those are the concrete, scientifically sound points.

A Practical Viewpoint

For how to use this in your life, I would mostly consider the role of color and your own experience. In my opinion, all legible dark mode schemes use bleak, washed-out palettes to maintain sufficient contrast. If you like those colors, then you will probably also like those schemes. Since the science says that color and contrast matter most, then go with the dark theme if that suits you. However, science also says that black text on a white background produces the best cognitive results.

But, if you prefer dark mode, remember that’s just your own preference. If you try to claim that it’s scientifically superior to light mode, you are factually incorrect. Also remember that software developers are software developers, not brain or eye doctors. They don’t get a vote on the science.