Despite this, graphic designers and others got used to them, making it practically impossible to introduce a different list.
In earlier releases of X11 (prior to the introduction of Xcms), server implementors were encouraged to modify the RGB values in the reference color database to account for gamma correction.
The list first shipped with X10 release 3 (X10R3) on 7 June 1986, having been checked into RCS by Jim Gettys in 1985.
Approximately the full list as is available today shipped with X11R4 on 29 January 1989, with substantial additions by Paul Ravelling (who added colors based on Sinclair Paints samples), John C. Thomas (who added colors based on a set of 72 Crayola crayons he had on hand) and Jim Fulton (who reconciled contributions to produce the X11R4 list).
The W3C specifications SVG and CSS level 3 module Color eventually adopted the X11 list with some changes.
[7] The present W3C list is a superset of the 16 "VGA colors" defined in HTML 3.2 and CSS level 1.
[12] The list of names accepted by browsers following W3C standards[13] slightly differs as explained above.
Actual rgb.txt files and other color databases or palettes may differ since they are freely editable by vendors and users.
The complete rgb.txt defines 101 shades from 'Gray0' (black) up to 'Gray100' (white) in addition to 'Gray' and its variants listed above.
The shades are apparently defined by the formula GrayN := round(N% × 255) resulting in e.g. 'Gray96' , which happens to be the same as 'White Smoke'.
Unlike base colors, e.g. cadet blue and CadetBlue, these are only coded without spaces, e.g. CadetBlue3.
The fixed brightness settings correspond closely to these formulae to determine the RGB values: color1 := color × 100% color2 := color1 × 93.2% color3 := color1 × 80.4% color4 := color1 × 54.8% Examples: Some color names appear to be brightness or saturation modifications of others because they bear prefixes such as Dark, Light, Medium, Pale or Deep, but there is no systematic variation apparent.
[18] This standard has four variants for each non-monochromatic color: clear (50% transparent), dark, light and the default.