White Text on Black Makes Me Want to Gouge My Eyes Out Like Oedipus
It’s hard to read, comprehend, and retain
It is not about aesthetics. Black-themed webpages project an air of elegance, luxury, prestige, mystery, and style. Like a black tuxedo, or the notable little black dress. They are beautiful to look at. However, they are hard to read.
White text on a black background — known as negative text — affects readability and comprehension.
Alyson L. Hill in her study Readability Of Websites With Various Foreground / Background Color Combinations… explains:
When light text is placed on a dark background the text may seem to glow and become blurred; this is referred to as halation, and it may make the text harder to read. (source)
The surprising fact about text-background relationship is that it not only affects readability, but also retention.
Richard Hall and Patrick Hanna in their study “The impact of web page text-background colour combinations on readability, retention, aesthetics and behavioural intention” demonstrate that black text on white background scores significantly higher than negative text on both readability and retention tests. (source)