What the research said
- The accepted answer reports that most studies have found dark characters on a light background superior for reading, provided the display refreshes quickly enough — a caveat that mattered more on the hardware of the time.
- It cites a 1980 study reported as finding participants around 26 per cent more accurate reading dark text on light.
- A second answer quotes an eye-strain specialist recommending black text on white, while noting other dark-on-light combinations also work well.
- These are the thread's citations rather than its own findings, and the primary sources are decades old.
The answer that is easier to act on
One reply reframed it as a question about the room rather than the screen. In a bright room the eye admits less light, so a dark background with small bright text becomes harder rather than easier. In a dark room a bright screen is the only lit object in view. Their preference was to match: light theme in daylight, dark theme at night — which is the behaviour navigation displays in cars have had for years, and now the reason operating systems switch themes on a schedule.
Where it genuinely depends
- Reading at night, where a dark theme is less disruptive — one contributor mentioned e-books in bed as the obvious case.
- Preserving night vision, or minimising light emitted, which is a requirement in some working environments.
- Visual impairment, which can reverse the general finding entirely for a given person.
- Personal experience, which the thread had plenty of on both sides and which nobody should be argued out of.
What this means if you are building something
- Offer both, and follow the operating system's setting by default rather than imposing one.
- Contrast matters more than direction: low-contrast grey text is harder work than either scheme done well.
- The evidence supports a light default for long-form reading, and does not support treating a dark theme as a health feature.