I was asked today to look into designing a stock monitoring windows 8 application and I was looking around for design ideas when I noticed an interesting trend where it seems like most of these stock monitoring or financial apps are on black or dark backgrounds.
Now I understand white text on a black background is generally used when we want to draw our attention to something but its not a good idea when there is a lot of information to read because of this reason (as per this article from UX Movement) :
The kind of text that users read is paragraph text. You should avoid using white text on a dark background when displaying paragraph text to make it easier from them to read. Forcing users to fixate on the white text for a long time can strain the user’s eyes. This is because white stimulates all three types of color sensitive visual receptors in the human eye in nearly equal amounts. This makes reading white paragraph text on dark backgrounds stressful on the user’s eyes.
White also reflects all wavelengths of light. Because the words and letters in paragraph text are compact and close together, when white text reflects light, the reflected light scatters and runs into neighboring words and letters. This makes the shape of the words and letters harder to perceive, which affects the user’s readability. Compare that with black text, where the black absorbs the light around each word and letter, making them easy to distinguish.
So my question is " Considering most financial apps show a lot of data which are often close together and dynamically updated, why do they use white text on a black background when it has been proven that it would be hard to read over a period of time"