From: "H.M.Hubey" Subject: Re: OF COLOUR MODELS, LANGUAGE, VECTOR SPACES and PHYSICS Date: Thu, 20 May 1999 00:13:02 -0400 Newsgroups: sci.lang,sci.med.physics,sci.math,alt.graphics,comp.graphics.misc To: bitte_nicht_stören danke "VeryNiceGuy (Magix)" wrote: > > the following articles are offshoots of the thread "Old English words > for color?" in news:sci.lang and readers in the other sci newsgroups > are invited to give their comments and critiques. See the article, Logic, physics, physiology, and topology of color, by H.M. Hubey, Brain and Behavioral Sciences, vol. 20, No.2, June 1997, p.191. it also has an article on algebra of color, and it is a commentary on an article on color, and there are also zillions of commentaries on color. You won't have to read anything else for a long time. -- Best Regards, Mark -==-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= hubeyh@montclair.edu =-=-=-= http://www.csam.montclair.edu/~hubey =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= ============================================================================== From: markrose@enteract.com (Mark Rosenfelder) Subject: Re: OF COLOUR MODELS, LANGUAGE, VECTOR SPACES and PHYSICS Date: 20 May 1999 18:33:30 GMT Newsgroups: sci.lang,sci.med.physics,sci.math,alt.graphics,comp.graphics.misc In article <3743E135.63E330FB@letterbox.com>, VeryNiceGuy (Magix) <"bitte_nicht_stören"@danke> wrote: >...> Are you aware that hue, brightness, and saturation are *not* >> independent? (and since HBS can be mapped to RGB, nether are RGB.) > >hue, brightness, and saturation independent among themselves >red, green, blue independent among themselves >BUT: hue, brightness, saturation, red, green, blue not independent > >perhaps you should learn some linear algebra? No, you should learn some visual science. Hue, brightness, and saturation are not independent in the visual system. If this is not taken into account in the mathematical model, the model is wrong. >> http://www.cogsci.soton.ac.uk/bbs/Archive/bbb.saunders.html > >couldn't find it. Replace bbb with bbs, sorry. ============================================================================== From: markrose@enteract.com (Mark Rosenfelder) Subject: Re: OF COLOUR MODELS, LANGUAGE, VECTOR SPACES and PHYSICS Date: 21 May 1999 19:39:32 GMT Newsgroups: sci.lang,sci.med.physics,sci.math,alt.graphics,comp.graphics.misc In article <37459EA8.EF103907@letterbox.com>, VeryNiceGuy (Pacific) <"bitte_nicht_stören"@danke> wrote: >Mark Rosenfelder wrote: >...> No, you should learn some visual science. Hue, brightness, and >> saturation are not independent in the visual system. > >howso? > >perhaps we are using different definitions? It's not a matter of definitions, but of simple models not correctly modelling human perception. Here's a description of the effect from David Hilbert's web page (http://www.uic.edu/~hilbert/Glossary.html): --- Bezold-Bru"cke hue shift: A shift in apparent color of a stimulus towards yellow or blue with increasing intensity. If a pair of long wavelength lights differing only in intensity are compared, the higher intensity stimulus will look more yellow and less red than the lower intensity light. For shorter wavelengths higher intensity lights look more blue and less green than lower intensity lights. There are three invariant points in the spectrum: monochromatic lights whose color appearance does not change with intensity. --- This can be hard to follow without a diagram. But, very simply, if you take your favorite color swatch, its hue will appear to change at low or very high levels of illumination. (And not in a linear way.)