Dark or white color theme is better for the eyes?
What is better for the eyes, a dark color theme or a white color theme?
You might also find related answers here : http://ux.stackexchange.com/questions/52833/which-color-scheme-to-choose-for-applications-that-require-long-work-hours/52947#52947
It can't be answered without understanding the full context of the application, the users, the content, the functionality, the use cases, etc, etc.
I'm curious, would the limitations of the display technology make a difference as well? Considerations include: How black is black, and how white is white? Do black pixels and white pixels get refreshed equally well? Is there more "bleeding" at the edge of a white pixel if the display is a light source rather than a reflective surface?
Some people are light sensitive. They commonly have to take steps to reduce white point. Be it allergies, a migraine or just eye-strain in general working 4-8 hours a day on a bright site or app. Its ok when your room is bright and you need the contrast. Even in presentations with projectors, you absolutely need the contrast. Something more subtle like a book or newspaper is far easier on my eyes. There are devices out there though that just can't get low enough for me. I associate these with a tanning booth or lightbulb.
Why was this question marked as a duplicate? It concerns programmers specifically, whereas the other question is more general.
One aspect no one seems to have mentioned is that if your IDE is white-text on black background, every time you context switch to the browser or almost any other app, you are presented with black on white. That makes for a very straining contrast as your eye now has to contract the aperture to reduce the light coming in.
I dumped dark colors for two reasons: they are inferior when the surrounding light is bright (daylight). In the night they're better, so you work in a console, but then you switch to a workspace with a browser, where website is mostly white and the amount of light burns your eyes. That's reason #2.
Really the biggest issue in this Q&A is that there is a significant difference between display and other reading, as well as various reading situations (long vs short, distance vs near, font size, legibility vs readability) — the question setup is all just way too vague.
There has been a lot of research on this topic since the 1980s and a lot of it still holds true today. One study from the 1980s states this:
However, most studies have shown that dark characters on a light background are superior to light characters on a dark background (when the refresh rate is fairly high). For example, Bauer and Cavonius (1980) found that participants were 26% more accurate in reading text when they read it with dark characters on a light background.
Reference: Bauer, D., & Cavonius, C., R. (1980). Improving the legibility of visual display units through contrast reversal. In E. Grandjean, E. Vigliani (Eds.), Ergonomic Aspects of Visual Display Terminals (pp. 137-142). London: Taylor & Francis
The reason why this matters is because of focus. As this article on UXMovement states, "white stimulates all three types of color sensitive visual receptors in the human eye in nearly equal amounts." It causes the eye to focus by tightening the iris. Since the eye is focused, dark letter forms on light backgrounds are easier to read. When using a dark background with strong light letter forms, the iris opens to allow more light in, but that causes letter forms to blur. Why?
People with astigmatism (approximately 50% of the population) find it harder to read white text on black than black text on white. Part of this has to do with light levels: with a bright display (white background) the iris closes a bit more, decreasing the effect of the "deformed" lens; with a dark display (black background) the iris opens to receive more light and the deformation of the lens creates a much fuzzier focus at the eye.
Jason Harrison – Post Doctoral Fellow, Imager Lab Manager – Sensory Perception and Interaction Research Group, University of British Columbia
Now there seem to be varying factors into contrast and legibility. Room ambient lighting. Brightness of the monitor. Also you can mitigate the straining effects of white (#FFF) on black (#000) by simply lessening the contrast like using a light gray (#EEE, #DDD, #CCC) on a dark background (#111, #222).
Update (Feb 7, 2020):
A new article from the Nielsen Norman Group entitled, "Dark Mode vs. Light Mode: Which Is Better?", brings some more research to this topic. A couple key findings in the article:
Cosima Piepenbrock and her colleagues at the Institut für Experimentelle Psychologie in Düsseldorf, Germany studied two groups of adults with normal (or corrected-to-normal) vision: young adults (18 to 33 years old) and older adults (60 to 85 years old). None of the participants suffered from any eye diseases (e.g., cataract).
Their results showed that light mode won across all dimensions: irrespective of age, the positive contrast polarity was better for both visual-acuity tasks and for proofreading tasks. However, the difference between light mode and dark mode in the visual-acuity task was smaller for older adults than for younger adults — meaning that, 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 research did find though that dark mode seemed to be beneficial for users with impaired vision:
In Legge’s study, each of the 7 participants with cloudy ocular media had better reading rates with dark modes, whereas the rest of the participants, who had impaired central vision, were not affected by contrast polarity.
Though they did note one caveat that this study used CRT displays instead of LEDs displays.
A few takeaways from the article:
- In general, light mode leads to better performance most of the time for users with normal or corrected-to-normal vision.
- While light mode performs better, those gain seem to be more short-term. Long-term exposure may be result in myopia.
- Increased font-size in dark mode doesn't offset the gains from light-mode.
- Providing a dark mode though is still recommended though becomes of the potential long-term effects with light mode, some visual impairments perform better in dark mode, and some users simply prefer it.
- For applications which provide long-form reading (books, articles, even news sites), dark mode options are recommended.
One other note with the studies cited in the article is that the studies focused on "glanceable" reading (i.e. reading 1-2 words on a mobile phone, smartwatch, or car dashboard).
- UX.SE Post: "Which color scheme to choose for applications that require long work hours?"
- Applying Color Theory to Digital Displays
- Why light text on dark backgrounds is a bad idea.
- When to Use White Text on a Dark Background
- Journal of Vision – Interaction of Ambient Lighting and LCD Polarity on Text Processing and Viewing Comfort
- Journal of Vision – Why is light text harder to read than dark text?
- NN/g - Light Mode vs Dark Mode: Which Is Better?
One factor to consider which I don't see mentioned is that for applications which require distinguishing the colors of many different objects, I think it's easier to judge colors against a black background than against white.
@Shimmy: How many different colors of text or thin-line-graphic objects would you be able to easily distinguish against a white background?
@supercat For me it's much easier to distinguish colors on a white background. I'm talking about recognizing those colors off screen. Maybe in real life it's different.
Could you point to more recent research on this? Because these results may simply be attributable to the low quality displays of the 80s, or responsible for a significant part of them.
I wish I had enough reputation to downvote this. White screens are straining on the eyes and can cause migraines. The cited studies were like short lab studied and not 8h work days.
This is just plain wrong. SMH. Probably this "research" was done by headache medicine companies. When I have a white screen accidentally come up on my machine, I can actually feel the headache starting. It hurts my eyes and my instinct is to look away from it. The white screen actually causes pain. How could my body be so wrong? It can't. The "research" is obviously wrong, or I'm special :)
Personally, I loathe dark backgrounds, and view them as a way to look geeky. More importantly, I do a lot of teaching, and I find that it is _much_ harder to read a dark colour them on a projected screen. Now, I know that projectors are never up to the standard of a modern screen, and there’s always the issue of room lighting. However, the classroom monitors are not top-of-the-line either. I have the feeling that if it’s harder in poor conditions, then it’s probably harder in good conditions, and our brains have to work harder to get useful results.
This research was done long before we knew about blue light. IANAO (I am not an ophthalmologist), but I imagine staring all day at an LED screen emitting high amounts of blue light is worse than looking at dark themes that have less blue in the spectrum.
I've seen that second quote, that astigmatism is a reason why some people prefer light themes, all over the Internet, but I can't find a **source** for that quote. Was this written somewhere? I'd like to point my colleagues to this post, but I am loathe to parrot uncited/uncitable information.
For me, a dark background in a dark room or a bright background in a bright room is ideal. Bright rooms causes the eye to let less light in, making dark backgrounds and the little bright letters even darker.
As for the dark room: being able to see the rest of the room is important for me to be able to look away from the screen now and then.
Have a look at GPS-devices for use in cars. They have different themes depending on the time of day.
I don't know if the GPS example is a great one because a bright GPS screen at night can be distracting to _other_ passing drivers. A bright GPS screen at night would also create a gross imbalance between the brightness of the road and that of the screen, leading to difficulty when repeatedly switching focus.
Computer vision syndrome expert Dr. James Sheedy:
"The best color combination for your eyes is black text on a white background, though other dark-on-light combinations also work well."
SOURCE: http://www.allaboutvision.com/cvs/irritated.htm (independent source of trustworthy information on eye health)
Personally for me light text on dark background strains my eyes, and that's why I have always wondered why so many colleagues use light text on dark background, and keep saying it's better for the eye, since for me only normal thing has been dark text on white background.
I have a hunch that statement was an over-generalization. It's never really been true in print, for example. Black on off-white or gray, sure...but not pure white.
@DA01 yeah, that's why the sentence ends "though other dark-on-light combinations also work well".
Two things that can make this an "it depends" issue are environment and visual impairment.
Using an app at night might make lighter text on a dark background better. For example, I find it less straining (and certainly less annoying to my wife) to use a dark background reading e-books in bed). Someone needing to preserve night vision or security, such as military or law enforcement, might also require much less light emission. Another factor might be the content displayed in an application. For instance, where the content is primarily videos or movies, a darker, more "cinematic" UI will be appropriate.
Some visual impairments require high-contrast for legibility and this is occasionally aided by being able to select a reversed foreground/background color set.
You may be talking about strain and not personal taste. One thing I know, though, is that it is somewhat physically painful to look at themes that have dark backgrounds with extremely bright (high brightness and saturation) foreground icons/text. If you choose dark backgrounds, lessen the brightness and saturation but make it still readable without effort.
White background with dark text is commonplace, and I haven't heard of any eye strain complaint about it. Bright backgrounds such as #00ffff (aqua) with dark text are very straining, though.