henry (08/04/82)
Actually, display terminals are a *worse* problem than phototypesetters. People doing phototypesetting have one big advantage: almost all their stuff is intended to be reproduced by printing processes, which cannot reproduce 1000 lines/inch. (In fact, it's a bit peculiar that people bother investing in 5000 lines/inch phototypesetters when all that extra resolution is totally wasted on the final product.) Trouble is, the human eye can see 1000 lines/inch jaggies. If you want a screen that looks like a printed page, yea unto the very limits of the human eyeball, you are going to need *even higher* resolution. On the other hand, if you are a reasonable man rather than one of the graphic-arts types who buys a 5000 lines/inch phototypesetter because when he looks at the original (*not* the mass-production product) with a magnifying glass he can see the dots in 1000 lines/inch output, then you may be able to content yourself with much lower resolution. I have heard that the critical resolution for "smooth looking" output is somewhat dependent on the dynamic range of light intensities, and CRTs actually are somewhat better off than paper (i.e. need less resolution to look good). There was a *very* interesting paper in Siggraph a year or two ago. The author (alas, I don't remember his name, and my Siggraphs aren't handy) claimed that standard NTSC resolution actually approaches the limits of the human eye, if used *right*. You need a good monitor, plus possibly some hardware fiddling so the scan lines touch each other (normally there is black space between them). You need *at least* 8 bits of gray scale, and your software must *USE* it properly. Oh yes, and your D-A conversion must be calibrated properly so that that 8-bit range really does turn into the right sort of range of light intensity. The explanation of why this works relies on things like halftoning effects, and I can't reproduce all of it off the top of my head; the key fact is that the resolution of the human eye is not a single number, but a complex phenomenon, and by doing things right you can do an end-run around resolution limits. Don't flame to me that it's impossible, read the article first. It's in one of the Siggraph conference proceedings, probably two years ago, titled something like "The 8000-line display". Henry Spencer utzoo!henry
ecn-pa.rick (08/04/82)
The SIGGRAPH article utzoo!henry mentions is: Human Vision, Anti-aliasing, and the Cheap 4000 line display William J Leler Texas Instruments Box 1433 M/S 617 Houston, TX 77001 It is contained in the SIGGRAPH'80 Conference Proceedings, which were published as Computer Graphics Volume 14, Number 3, July 1980. It is definitely worth reading for those concerned with increased display resolution. Rick Adams Purdue University