Roentgen and Retina displays are in the neighborhood of 200 ppi, which is about when laser printers became 'clear' and legible, which was the thesis behind Roentgen.
But now you've got smart phones pushing in the region of 400 PPI. It's smoother, and make Apple displays look like laggards. But they're beyond the point where most eyes notice the difference without magnification.
But now you've got smart phones pushing in the region of 400 PPI. It's smoother, and make Apple displays look like laggards. But they're beyond the point where most eyes notice the difference without magnification.