Friday, October 31, 2008

Density Changes The Visuals

In 1996, while I was knee-deep in medical computing, one of the press releases that caught my eye was about Xerox spinning off a display company for displays with a very high pixel density, around 300 pixels per inch. Your average computer display has 72 pixels per inch, newer ones do 96. 300 pixels per inch is in the league of newspapers and the first home laserprinters to be deemed 'good enough for professional use'. This means the dots used on a computer screen are very big compared to paper, which is why a straight diagonal line on a screen looks jagged unless smoothing tricks like 'anti-aliasing' are used. You can make very detailed graphs and charts at 300 dpi, which you cannot at 72 or 96 dpi, which is why you can still cram more static information on a printed sheet than on a computer screen. So this new company was making displays comparable to paper, which they were positioning as display devices for medical use like reading electronic X-rays, or for the defense industry. Meanwhile I was facing the problem that there was no way I could put all the information contained in a single front sheet of a medical record, with its graphs and annotations, on a computer screen. Especially since 640x480 was a good screen then.

Sharp's 'FULLTOUCH 931SH' mobile phone for Japan

Well, it is ten years later, and Sharp has just announced this phone that, at 1024 x 480 in a 3"8 diagonal screen is getting very close to that magic 300dpi number. Ok, first of all, that means the graphic chip inside that box could probably get away with less aggressive anti-aliasing routines, as jagged lines look far less jagged when the dots making up the line are so small. Also, you could probably display 6 point lettering and have it still be readable.

This display is still not a reflective dislay like a piece of paper is; a display like this emits light from behind the lettering which makes it less easy to read than a well lit piece of paper. And making displays of this density is really difficult -- with every extra pixel added the chance a pixel on the screen won't work goes up -- so yields are probably very low unless you keep the displays small, so we won't have our A4 / Legal-sized screens of newspaper density any time soon. But still, this is getting really close to a properly useful handheld medical record, or handheld inventory list, or handheld visualizer of complex financial data, or just a darn good comics reader that does the artwork justice. Charts and graphs and lay-outs currently used on computer screens are just not up to using the visualization potential of these densities. It's time to look at the most intense information visualization techniques used on paper, the ones before desktop computing took off, and evolve from there, like Edward Tufte has done all through these display-oriented decades. Densities like this will also accelerate the move away from the cartoonesque user interfaces and more towards photographic realism, where objects look like their real-world counterparts, black outlines around elements are no longer necessary, and textures like water, leather, fur, and metal will be rendered so close to realistic they might actualy look good as backgrounds.