hwt@bnr-public.uucp (Henry Troup) (11/03/88)
Followups to comp.text... I happen to have the recent book _Digital_Typography_, Richard Rubenstein, Addison-Wesley, 1988, ISBN 0-201-17633-5. On page 111, he says On some kinds of output device... there is the possibility of using greyscale... for minimizing jaggies and creating more subtle shapes. This technique works because of tthe eye's ability to enhance edges when viewing shapes. Instead of seeing a soft edge, as actually displayed, a sharper one in an intermediate position is perceived. This useful ability allows intensity information to be substituted for spatial information.... Indeed, ...television... By careful design... avoids high frequencies during sampling that could cause alaising, and avoids reconstruction errors during display. ... Grey levels are particularly useful on displays with very limited spatial resolution, such as conventional TV sets used to display text. They have the additional benefit of diminishing text flicker resulting from interleaving, because greyscale equalizes the intensity between adjacent parts of letters in different fields. I highly recommend the book, as Rubenstein deals with many factors affecting WYSIWIG and its unattainability. He discusses the impact of the device characteristics (CRT, laser printer, etc) on font rendering, and why one set of fonts will not serve all purposes. (TeX users already know about write-white and write-black fonts). Henry Troup utgpu!bnr-vpa!bnr-fos!hwt%leibniz | BNR is not Bell-Northern Reseach hwt@bnr (BITNET/NETNORTH) | responsible for my Ottawa, Canada (613) 765-2337 (Voice) | opinions