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Contents of README:This directory contains several alternative rgb databases: old-rgb.txt the version that was shipped in previous releases; this was originally "tuned" for the Digital VT240 series terminals. raveling.txt lots of new colors, tuned by Paul Raveling at ISI for the HP monitor; see below. thomas.txt a version of the older database that was tuned by John Thomas at Tektronix to match a box of Crayola crayons; see below. Notes from Paul Raveling: 1. Many colors have been tuned for an HP monitor -- mine, to be exact. Some of the old values were obnoxious enough to bring complaints from users (like "That's Wheat???!!!"); so far early user reports on the new RGB database are favorable. 2. File rgb.txt was reorganized into 3 sections: a) Light and off-white colors, copied from several Sinclair Paints color samples. The intent for adding these is to provide a better choice for light-colored window backgrounds. BTW, I wanted to find ANSI standard colors, but ANSI happily gobbled my $16 without sending the specification I ordered, Then they ignored my followup letter. Nuts to ANSI & "ANSI standards". b) Special colors such as black, white, and favorite shades of gray. c) A spectrum of colors, arranged to transition gradually between nearby colors, running from generally blue colors through green and ending with generally red colors. This includes all colors from the old X11R3 database, but they're no longer in (mostly) alphabetic order. d) The gray scale from the original X11R3 database. Within the "spectrum of colors" section there are clusters of colors, each consisting of: 1. One or more Specially named colors. If more than one is present, all are related by lying on a common line running from RGB = (0 0 0) [pure black] to a single point on the surface of the RGB color cube. 2. Four colors at particular points on the same line in RGB space. Their names end in "1", "2", "3", and "4", with "color1" being at the surface of the color cube and the others at increasing distances approaching black. Distance of these color points from black is approximately logarithmic. This attempts a rough fit to human perception's sensitivity to intensity. Here's an example of one of these clusters: 210 105 30 chocolate 139 69 19 saddle brown 139 69 19 SaddleBrown 255 127 36 Chocolate1 238 118 33 Chocolate2 205 102 29 Chocolate3 139 69 19 Chocolate4 Note that the "original" colors, in this case chocolate and saddle brown, don't always match the scaled points. Does anyone think these changes are a good idea? Crummy idea? Do you have other favorite colors? Can anyone do better at matching some tough colors? Some colors, especially reddish ones, were VERY hard to reproduce, & I'd welcome contributions from other HP users who can get a better match. Notes from John Thomas: Advised by our human factors folks that "standard" named colors exist, but only for well-controlled color coordinate systems (like CIE, but not for RGB), I sat down one evening with the handiest standard of subjective color names, a box of 72 Crayola crayons. (Believe it or not, over 50% of the colors from rgb.txt were represented.) Using an X-client implementation of the TekColor model, I created the following list of named colors. Appearance on your monitor may vary because of brand, age, and video drive circuitry, but I think you will find it a better match for the average monitor, than the original rgb.txt file from MIT. John C Thomas Tektronix, Inc. Wilsonville, OR jct@windex.TEK.COM |
Name Last modified Size
Parent Directory -
CVS/ 19-Mar-2020 23:40 -
README 30-Jul-2008 06:09 4.2K
old-rgb.txt 30-Jul-2008 06:09 6.4K
raveling.txt 30-Jul-2008 06:09 16K
thomas.txt 30-Jul-2008 06:09 5.4K
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