Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: Notesfiles $Revision: 1.6.2.16 $; site datacube.UUCP Path: utzoo!watmath!clyde!burl!ulysses!ucbvax!decvax!cca!datacube!shep From: shep@datacube.UUCP Newsgroups: net.graphics Subject: Solarization and Posterization Message-ID: <6700033@datacube.UUCP> Date: Thu, 19-Sep-85 21:28:00 EDT Article-I.D.: datacube.6700033 Posted: Thu Sep 19 21:28:00 1985 Date-Received: Sun, 22-Sep-85 23:57:58 EDT Lines: 32 Nf-ID: #N:datacube:6700033:000:1542 Nf-From: datacube!shep Sep 19 21:28:00 1985 Solarization and Posterization. We here these terms and most of us familiar with them picture the effect mentally: An image with some type of luminance or chromanance quantization and/or mapping. But what do they REALLY mean and what are their origins? I believe solarization came from the photographic effect of exposing emulsion to light sometime during development. I have no idea where the term posterization came from. Can anyone answer these questions? I worked on a popular television special effects box that has what I called solarization and posterization. The solarization name was given to all the lookup table effects performed on only the y (luminance) signal. As we quantized luminance to progressively fewer states, we said the image was more "solarized". Similarly, the "posterization" term was applied to quantization of the chromanance difference components. I recently received mail from a friend asking me about the subject... >Subject: solaraposterization >Just what are solarization and posterization? You are the world expert on >these matters now that you have become an ancient one. ... >Is a table look-up on luma and chroma independently enough or do >you have to provide LSD-like cross leakage between luma and chroma? and I remembered that I had found references that spoke of quantization in polar (hue/sat/val) space. Does anyone know of these references or algorithms? Shep Siegel UUCP: ihnp4!datacube!shep Datacube Inc.; 4 Dearborn Rd.; Peabody, Ma. 01960; 617-535-6644 Brought to you by Super Global Mega Corp .com