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There is somewhat general scientific agreement that in general case for reading, dark text on light background is more readable than light on dark.

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

People with astigmatism (aproximately 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 (source: Tatham Oddie "Why light text on dark background is a bad idea")

Above is however generic, not computer screens in particular.

Most modern study I've found regarding computer screens is the studies I've found ("The impact of web page text-background colour combinations on readability, retention, aesthetics and behavioural intention" by Hall & Hanna, 2004) did not measure prolonged exposure. Also these test were performed on random people, not professionals who spend long hours with text (code).

On the other hand I see, that all kinds of dark themes are quite popular, and even default in various IDEs. It seems as contradiction if so many programmers would willingly choose less ergonomic color schemes.

So are there any studies of the subject that take in account modern screen technology and type of work typical ITC professional is doing?

Loosely related to: Is it preferable to use a computer in a darkened room?
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  • So the claim is "Dark text on white screens is more readable on computer screens."? Who is making that claim? – Oddthinking Nov 11 '11 at 11:12
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    No. "Dark text on white screens is more readable on computer screens." is already answered/proven. Claim is that it also holds for programmers working with code 8h+ a day. On modern computer screen (there have been some studies about that relating to CRTs, which is now obsolete) – vartec Nov 11 '11 at 11:16
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    Okay, so who is specifically making the claim about the 8h+ coders? (My concern here is this question is a research-level question about a topic that hasn't yet been explored by the science, rather than someone making a dubious claim.) – Oddthinking Nov 11 '11 at 12:31
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    Anecdotally, the majority of programmers I know prefer a bright color on a dark background. Bright green text on a black background seems to be the most popular. Those users cite the fact that, with prolonged use, having a bright background would strain the eyes. vartec is pointing out that these claims contradict the well established fact that for *instantaneous* exposure dark text on a bright background is more readable. So I think what he's asking is: "Which color scheme is more beneficial for prolonged exposure?" – ESultanik Nov 11 '11 at 13:35
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    @Oddthinking - would a default color scheme chosen by a major programming IDE vendor be a good enough notable (but implicit) claim? Say, MS Visual tools + Eclipse? – user5341 Nov 11 '11 at 14:30
  • @Oddthinking there are quite a few usability and ergonomic studies that have found this. Not to mention the link he provided in the original question. – Chad Nov 11 '11 at 14:48
  • @ESultanik, if your last sentence is true, this is out-of-scope of Skeptics.SE. – Oddthinking Nov 11 '11 at 15:30
  • @DVK: No, the colour choices may be arbitrary, may be chosen to be distinctive from the apps being developed (I often use background colour as a cue to which app/machine I am using) or may be a marketing decision. – Oddthinking Nov 11 '11 at 15:32
  • @Chad: I am not sure what you are saying the studies have found. We are trying to find someone making a statement that vartec is skeptical about. Hall & Hanna apparently didn't. – Oddthinking Nov 11 '11 at 15:36
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    Bright colors on a dark background allow you to distinguish more different colors (at good contrast) than dark colors on a bright background. One can speculate that this makes syntax highlighting more useful, but I haven't seen any studies on it. – Rex Kerr Nov 11 '11 at 16:55
  • This is a _very_ notable argument among programmers http://stackoverflow.com/questions/498698/white-light-vs-black-dark-backgrounds-health-effects - not sure if that qualifies it for Skeptics, though. – dtanders Nov 11 '11 at 19:56
  • @Oddthinking: claim is "light on dark schemes are better for programming" and it's claim made by significant part (or even majority) of programmers. If you need someone in particular to make that claim, here: http://goo.gl/sJ4e – vartec Nov 13 '11 at 18:55
  • @vartec: I agree we are getting very close, but that article doesn't make that claim. – Oddthinking Nov 13 '11 at 19:27
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    @Oddthinking: according to http://meta.skeptics.stackexchange.com/questions/864/faq-must-all-questions-be-notable *"common knowledge"* is acceptable as claim. And as I see it, there is more than enough evidence here to support, that it's "common knowledge" among programmers. – vartec Nov 14 '11 at 09:20
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    @vartec: Note I haven't closed this question, or even downvoted it. I am trying to get it from a good question to a great one. So far, we've seen a paper claiming that the one way is better for short-term eyestrain, and no-one is doubting that. We've seen programmers claim they prefer the other way, and no-one is doubting that. You wonder if there is a possibility that long-term might be different to short-term, and no-one seems to be making a counter-claim. The question is lacking a certain frisson of disagreement. – Oddthinking Nov 14 '11 at 09:30
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    The problem I have with claims for this that I've heard/read over the years is that they don't take into account that each person's eye sight seems to have different qualities -- what some folks find too bright, others find too dark, or too large vs. too small, or too close vs. too far, etc. Personally, I can see better in the dark than almost everyone I know, but I also need to wear sunglasses throughout most of the day (for comfort) while other people normally don't, so I prefer (particularly green or lime text) on a black background, especially when programming. – Randolf Richardson Nov 14 '11 at 09:46
  • from personal experience I can say that for me at least, dark text on a bright background is over hours more tiring to look at, while bright text on a dark background takes a bit longer for the eyes to adjust to at first exposure. – jwenting Nov 14 '11 at 11:14
  • from my own experience using dark back grounds when staring at a computer screen for hours was less strenuous on my eyes and i get fewer headaches from staring at monitor for too long this is likely more to do with light emitted from the screen as opposed to the perceived em radiation giving off from a crt monitor as i get similar effects from either crt or lcd i would say the effects are based on light is plausible to conclude that using a dark background may help in this department whether that is percieved or or hard medical fact is irrelevant imo – Chris McGrath Nov 15 '11 at 22:36
  • The media is very important. Modern displays are quite different from paper and each other: glossy vs matte, PWM vs non-PWM. See my non-scientific answer on UX: http://ux.stackexchange.com/a/25330/5775 – Sergey Sep 03 '12 at 15:07
  • @Sergey: PWM would mean CRT, which has zero relevance nowadays. – vartec Sep 03 '12 at 15:29
  • @vartec most of the modern LCDs use PWM to emulate average brightness. – Sergey Sep 03 '12 at 18:26
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    During day time my Apple Cinema Display has too much glow when displaying dark background (day light reflected from bright walls). Coding at night adds another angle. I want to be able to code for 1-3 hours at night without disrupting sleep too much. With lights turned off, light text over dark background *might* be more ergonomic due to lower contrast between my surroundings and computer screen. Also light background emits too light which in itself is harmful for sleep (http://stereopsis.com/flux/research.html), but this does not relate directly to the question. – Wojtek Kruszewski Sep 26 '12 at 10:32
  • @Wojtek: to use Apple Cinema Display (or any glossy screen for that matter) is pure masochism anyhow. – vartec Sep 26 '12 at 11:02
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    @vartec Given that you see yourself most of the time, this depends how handsome and narcissistic you are. Glossy screen also reminds you that it's time for haircut. – Wojtek Kruszewski Sep 26 '12 at 19:48
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    @Fabian you just deleted my answer with no further info. You could have at least pointed out the bits you didn't like first. – NimChimpsky Sep 27 '12 at 15:55
  • One thing related but also to consider: current trend isn't so much bright on dark or v.v. but more and more color schemes using a low contrast scheme. – Pieter B Mar 29 '13 at 11:45
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    I use bright colors on a dark background because I saw it on a movie about a hacker infiltrating someone's machine. – Saturn Mar 30 '13 at 23:06
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    Dont see how this is relevant => ("The impact of web page text-background...) . Reading and programming are different forms. Different parts of the brain are used and your eye most certainly does not work in the standard top - bottom -left -right manner. Another thing to take into account is that a lot of programmers work at various hours of the day. When the eye is preparing to sleep environmental factors change slightly. High concentration might be achieved by light on dark, to account for light sensitivity during these times. –  Jun 24 '14 at 08:53
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    When asking if it's "better" for programmers, shouldn't the answer (or study) include how well multi-colored text can be distinguished against different backgrounds? Having stared at code for many years myself, I find that much of my time is spent scanning for patterns, indentation and syntax, including the syntax-highlighting which is color-coded. I rarely read text in code linearly, the way I would read a book. – Dynrepsys Nov 26 '14 at 16:00
  • yes.yes.yes.yes.yes. – crh225 Aug 14 '15 at 16:43
  • I personally strongly prefer dark colours, but I suspect that this might be too subjective to come up with a definitive answer, it's largely going to come down to personal preference – GordonM Sep 02 '15 at 09:19
  • @ESultanik, *"the majority of programmers I know prefer a bright color on a dark background"*.. And what are their **ages?** Many people are influenced by Hollywood and like to look cool, especially the 20+ and 30+. Real coders who have been in the field for a long time do not use black background. – Pacerier Sep 29 '15 at 11:43
  • @Pacerier My gramps is an old-time DBase III/Clipper programmer. There was no such thing as Hollywood influence towards coders when he started. His favorite color scheme is light gray text on a deep dark blue screen. He isn't a "real coder" to you? Most hollywood movies copy the coders, not the other way around. Back then bright on black was _all the rage_! – T. Sar Oct 03 '16 at 15:21
  • @Pacerier In my experience it's not about age at all. Where I work about 90% of those using editors with an option to use a dark background do so, independent of age. From personal long experience I can affirm that at least for me it makes for a more pleasant work experience with less eye strain and fatigue than a bright background. It does depend on the screen though, a dim/low contrast screen benefits from a brighter background. – jwenting Oct 09 '16 at 05:24

1 Answers1

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  1. "Typically greater brightness of positive compared to negative polarity displays leads to smaller pupil sizes and, hence, a sharper retinal image and better perception of detail."

Per Piepenbrock C et.al. in 2014, the results of the study are compatible with the hypothesis that the positive polarity advantage is an effect of display luminance.

  1. "Dark characters on light background lead to better legibility and are strongly recommended independent of observer's age."

Per Piepenbrock C et.al. in 2013, "participants conducted a visual acuity test with black optotypes on white background or white optotypes on black background and performed a proofreading task in the same polarity. A positive polarity advantage was found for both age groups. The presentation in positive polarity is recommended for all ages."

PRACTITIONER SUMMARY: In an ageing society, age-related vision changes need to be considered when designing digital displays. Visual acuity testing and a proofreading task revealed a positive polarity advantage for younger and older adults

  1. "Readability of text presented on computer screens (e.g. on websites) is better when the overall display luminance level is high, as in positive polarity displays (dark letters on light background)."

Per Buchner A et.al. in 2009, display polarity per se does not affect readability. Contrast polarity is one aspect of reading that has been studied in detail for visual acuity which relates to clarity of vision. It designates whether text is presented as black letters on a white background or vice versa.

  1. "Typically higher luminance of positive polarity displays leads to an improved perception of detail" per Piepenbrock C et.al. in 2014,

Dark characters on light background (positive polarity) lead to better legibility than do light characters on dark background (negative polarity), presumably due to the typically higher display luminance of positive polarity presentations. The implications seem important for the design of text on such displays as those of computers, automotive control and entertainment systems, and smartphones that are increasingly used for the consumption of text-based media and communication. The sizes of these displays are limited, and it is tempting to use small font sizes to convey as much information as possible. Especially with small font sizes, negative polarity displays should be avoided.

  1. "Background color did not significantly affect visual acuity when studying the effects of color combination on the visual acuity and display quality using TFT-LCD. The results also indicated that chromatic background may be more appropriate than achromatic background (gray) for TFT-LCD work" per Chin-Chiuan Lin et.al in 2006. However, these results are contradictory to the findings that chromaticity contrast has a profound effect on visual performance, but matched with previous findings that chromaticity contrast cannot improve the legibility. Per the researchers, further investigation is required in the interaction effects between contrast ratio and screen luminance combinations on visual acuity and display quality with TFT-LCD.

Further, in visual performance test (psychology measure), the objective and subjective measures were often consistent in the prolonged test, such as reading and proof-reading tasks; and were often inconsistent in the short term test, such as identification and legibility tasks. It’s very difficult to explain why the inconsistency of subjective and objective results. One possible reason is the visual fatigue. In prolonged test, subjects might produce visual fatigue.

Background color also did not affect the visual acuity. The effects of background color on visual evaluation might depend on the type of measure. Contrarily, background color did have a significant effect on subjective rating. The subjective ratings on background with blue, cyan, green and purple color were significantly greater than that with red. Further, we conclude that subjects may favor cool colors than warm colors as for background color.

  1. "In general, the plain backgrounds led to faster search times than did the medium-textured backgrounds, and blue backgrounds led to slower and more variable search times than the grey or yellow backgrounds" per Alyson L. Hill et.al. in 1999

The interactions indicate that one can not make simple predictions regarding factors which lead to efficient processing. Further, search times did not correlate with participants' preference ratings of the different stimulus combinations. Designers should keep this in mind when designing software and web pages.

  1. "Search times indicate that these background variations only affect readability when the text contrast is low, and that spatial frequency content affects readability" per Lauren F. V. Scharff et.al in 2000 who has published several papers on readability of text displays.

  2. "Performance was significantly worse for the low text contrast, the additive combination rule, and the "culture" pattern and both patterns were worse than the uniform background" per Lauren F. V. Scharff et.al in 2001.

Per David L. Post's Color in Electronic Displays, "visual acuity was not substantially affected by chromaticity, when given adequate contrast, photopic viewing conditions and reasonable symbol sizes. Conversely, acuity is not affected much by luminance contrast, given adequate chromatic contrast."

For low vision observers

Many low-vision observers prefer white-on-black text per Sloan 1977. Legge et al. in 1985 demonstrated that low-vision subjects with cloudy ocular media read faster with white-on-black text. This effect is probably due to abnormal light scatter in the eye. Upper-case is more legible than the other case styles, especially for visually-impaired readers, because smaller letter sizes can be used than with the other case styles, with no diminution of legibility and two other studies by Martha Ziefle suggest that one of the main contributors to slower reading performance, at least after 30 minutes, could be the resolution of the characters being read.

For normal vision observers

"Unfortunately, word readability is not necessarily simply related to letter identifiability and simple contrast measures". There has been several reported small advantages in normal reading performance for black-on-white text, especially for small letters. However, Legge et al. in 1986 found no systematic effect of contrast polarity in their study of the reading performance of subjects with normal vision since reading rates showed no effect of chromaticity at any of the character sizes studied. This experiment measured reading rates for monochrome text on CRT using a black background and either red, blue, green or white raster scan characters. Normal subjects usually read static text more rapidly. The reverse was true for low-vision subjects; their reading rates for drifting text were slightly higher (average 15%) than for static text. Most people with low vision are handicapped in reading and for many people, reading difficulty is the most serious consequence of eye disease. Per Shen Y et.al. in 2014, varying background luminance to maintain screen background luminance ratio is beneficial to human visual comfort.

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