My plea to designers and software engineers: Ignore the fads and go back to the typographic principles of print — keep your type black, and vary weight and font instead of grayness.

It wasn’t hard to isolate the biggest obstacle to legible text: contrast, the difference between the foreground and background colors on a page. In 2008, the Web Accessibility Initiative, a group that works to produce guidelines for web developers, introduced a widely accepted ratio for creating easy-to-read webpages.To translate contrast, it uses a numerical model. If the text and background of a website are the same color, the ratio is 1:1. For black text on white background (or vice versa), the ratio is 21:1. The Initiative set 4.5:1 as the minimum ratio for clear type, while recommending a contrast of at least 7:1, to aid readers with impaired vision. The recommendation was designed as a suggested minimum contrast to designate the boundaries of legibility. Still, designers tend to treat it as as a starting point.