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Note about dark userinterface themes
Last updated at 12:00 pm UTC on 29 August 2017
Markus Stumptner
Tue, Aug 29, 2017 at 6:02 AM
Reply-To: Any question about pharo is welcome
To: pharo-users@lists.pharo.org

On 28/08/17 06:07, Dimitris Chloupis wrote:
> I completely agree - dark mode is great for content that you want to
> look cool, but no one consumes. :-)
> You assume wrong cause dark themes have been dominating GUIs for over 3 decades now.

Not really; bright on dark was only dominant in the days of the CRT terminal when there were no "themes". (Even if you could do it as a hardware switch, setting, say, a VT220 to black-on-white both looked terrible as it was more an uneven gray, and tended to dim the tube more quickly by burning in the background.)

Instead, since full bitmap graphics happened, all screen interfaces back to Xerox's prototype office systems, then Lisa/Macintosh, and then Windows 2.1 have been using dark type on a white background for text work. Partly this was because of the original office metaphor, but partly also because it was shown that it was easier (meaning, less error prone) to read.

Here's a study that showed that participants were 26% more accurate in reading text that way (note that "contrast reversal" on displays in those days meant dark characters on white background):

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

There were other studies in the 1980s that didn't report lower errors but instead faster reading with black on white. Academically, the matter's pretty much considered settled - black on white is better for most of the population, and that's on screen, not on paper. (You can substitute any degree of light or creamy for the white, that's really a variation of screen quality.)
The engineering workstations of the late 80s and 90s (Sun etc) used black and white as the application default as well, with white on black limited to console/shell windows. This was partly for consistency with the old style, partly for easy contrast with application windows in a multi-window environment.

> Pharo was the rare exception of using a white theme. Light themes may be popular but white are definitely not. The web is the last fort of bright themes, but the web was and still is eons behind when it comes to matters of UI.
Most other Smalltalks are dark-on-light by default all the way back to Smalltalk-80 out of Xerox PARC. None of this had anything to do with the Web, which came after, but which obviously also profits from the same increase in readability. Rather than behind, Smalltalk was ahead and the rest of the world followed.

The dark theme as default in Pharo I personally consider a step back. As someone who's been busy for 25+ years defending use of Smalltalk for real applications, a return to a primarily developer-cool presentation instead of a user-oriented default is IMO not a plus for a language branch that was billed as more industry-oriented (which IMO is not exactly the same as developer-oriented). But I also understand the desire to attract developers with the look that's currently fashionable.

That said, I wonder if the recent preference for dark among developers (not Pharo-specific, but many languages) has to do with the rise of widespread code highlighting. I could see how colour highlighting shows up better on a dark background than being glared over by a white one.