Really love this piece of technical analysis by Anandtech's Joshua Ho regarding the technical merits of increasing pixel density on phone and tablet screens. Joshua dives deep not only on intrinsic manufacturing and energy costs of building increasingly high-resolution displays for phones (Samsung's next Galaxy smartphone is rumored to have a 5-inch 2560x1440 screen), but also the limits of human perception--which aren't as clearcut as they seem. Several things jumped out at me from reading the piece. First, that PPI as a standard for screen quality is relatively useless, as pixels per degree (PPD) and sub-pixels per inch (SPPI) are arguably better metrics that take into account qualitative use cases and screen manufacturing technologies. Second, that there is an important difference between the technical limitation of human eye acuity and a person's perceptual capabilities, because the brain does some interpolation in its processing of photons. And third, that this may be the beginning of a shift away from PPI (a concept Apple bought into the mainstream) as a talking point for consumers. It's really interesting to follow along as users (and reviewers) get more informed about the minute technical aspects of new devices, and to see the salient marketing points that manufacturers push to the public shift along with it. We've seen that in smartphone displays (a shift from screen size to pixel dimensions to pixel density) as well as consumer cameras (shifting from megapixels to sensor size to lens ecosystem). As users become more tech savvy, the marketers have to find new ways to spin their tech talk and try and pull wool over our eyes.