Apple has led the world into a new era of high-definition screens for mainstream computers with its "retina display" technology for the MacBook Pro, bringing such high pixel density that the eye is unlikely to notice individual pixels. With other computer manufacturers likely to follow (many mobiles already have such high-definition screens), Web usability expert Jakob Nielsen, in his Alertbox newsletter, says it's time to rethink Verdana and other sans-serif fonts we have been using.
Mr. Nielsen is shocked it took so long to reach this state of better viewing: In 1998 he predicted that decent monitors with 200 pixels per inch – the level at which high definition begins – would be available within five years.
Now, long after that, Apple has come in with 220 PPI, well under the 900 PPI for a screen so good that adding pixels wouldn't make it look any better. But given that astute Web designers have been using sans-serif fonts because poor screen definition made serifs blurry, we need to be more flexible.
He notes that almost all mainstream printed newspapers, magazines and books use serif type, so people are more accustomed to reading long texts in that style. The difference in speed of reading between serif and sans serif is quite small, according to the research.
He suggests that in the coming high-definition world, you can ignore readability when choosing fonts and make choices on other factors such as branding or the mood communicated by a particular typographical style.