computing Computing is any goal-oriented activity requiring, benefiting from, or creating computer, computing machinery. It includes the study and experimentation of algorithmic processes, and the development of both computer hardware, hardware and softw ...

, on the

X Window System The X Window System (X11, or simply X) is a windowing system for bitmap displays, common on Unix-like operating systems. X originated as part of Project Athena at Massachusetts Institute of Technology (MIT) in 1984. The X protocol has been at ...

, X11 color names are represented in a simple text file, which maps certain strings to RGB color values. It was traditionally shipped with every

X11 The X Window System (X11, or simply X) is a windowing system for bitmap displays, common on Unix-like operating systems. X originated as part of Project Athena at Massachusetts Institute of Technology (MIT) in 1984. The X protocol has been at ...

installation, hence the name, and is usually located in ''<X11root>''/lib/X11/rgb.txt. The

web colors Web colors are colors used in Web design, displaying web pages on the World Wide Web; they can be described by way of three methods: a color may be specified as an RGB color model, RGB triplet, in hexadecimal format (a ''hex triplet'') or acc ...

list is descended from it but differs for certain color names. Color names are not standardized by Xlib or the X11 protocol. The list does not show continuity either in selected

color value Lightness is a visual perception of the luminance (L) of an object. It is often judged relative to a similarly lit object. In colorimetry and color appearance models, lightness is a prediction of how an illuminated color will appear to a stand ...

s or in

color name A color term (or color name) is a word or phrase that refers to a specific color. The color term may refer to human perception of that color (which is affected by visual context) which is usually defined according to the Munsell color system, or ...

s, and some color triplets have multiple names. 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. As of X.Org Release 7.4 rgb.txt is no longer included in the roll up release, and the list is built directly into the server. The optional module xorg/app/rgb contains the stand-alone rgb.txt file. The list first shipped with X10 release 3 (X10R3) on 7 June 1986, having been checked into

RCS RCS may refer to: Organizations Arts and entertainment * Radio Corporation of Singapore * Radcliffe Choral Society, a choral ensemble at Harvard University *RCS MediaGroup (Rizzoli-Corriere della Sera), an Italian publishing group *Royal Conserva ...

Jim Gettys Jim Gettys (born 15 October 1953) is an American computer programmer. Activity Gettys worked at Digital Equipment Corporation, DEC's Cambridge Research Laboratory. He is one of the original developers of the X Window System at MIT and worked ...

in 1985. The same list was in X11R1 on 18 September 1987. 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 Crayola LLC, formerly the Binney & Smith Company, is an American manufacturing and retail company specializing in list of art media, art supplies. It is known for its brand ''Crayola'' and best known for its crayons. The company is headquartered ...

crayon A crayon (or wax pastel) is a stick of pigmented wax used for writing or drawing. Wax crayons differ from pastels, in which the pigment is mixed with a dry binder (material), binder such as gum arabic, and from oil pastels, where the binder is a ...

s he had on hand) and Jim Fulton (who reconciled contributions to produce the X11R4 list). The project was running DEC VT240 terminals at the time, so would have worked to that device. In some applications multipart names are written with spaces, in others joined together, often in

camel case The writing format camel case (sometimes stylized autological, autologically as camelCase or CamelCase, also known as camel caps or more formally as medial capitals) is the practice of writing phrases without spaces or punctuation and with cap ...

. They are usually matched insensitive of case and the X Server source code contains spaced aliases for most entries; this article uses spaces and uppercase initials except where variants with spaces are not specified in the actual code.

Clashes between web and X11 colors in the CSS color scheme

The first versions of

Mosaic A mosaic () is a pattern or image made of small regular or irregular pieces of colored stone, glass or ceramic, held in place by plaster/Mortar (masonry), mortar, and covering a surface. Mosaics are often used as floor and wall decoration, and ...

and

Netscape Navigator The 1990s releases of the Netscape (web browser), Netscape line referred to as Netscape Navigator were a series of now discontinued web browsers. from versions 1 to 4.08. It was the Core product, flagship product of the Netscape, Netscape Comm ...

used the X11 colors as the basis for the

list, as both were originally X applications. The

W3C The World Wide Web Consortium (W3C) is the main international standards organization for the World Wide Web. Founded in 1994 by Tim Berners-Lee, the consortium is made up of member organizations that maintain full-time staff working together in ...

specifications SVG and CSS level 3 module Color eventually adopted the X11 list with some changes. The present W3C list is a superset of the 16 "

VGA Video Graphics Array (VGA) is a video display controller and accompanying de facto graphics standard, first introduced with the IBM PS/2 line of computers in 1987, which became ubiquitous in the IBM PC compatible industry within three years. T ...

colors" defined in HTML 3.2 and CSS level 1. One notable difference between X11 and W3C is the case of "Gray" and its variants. In HTML, "Gray" is specifically reserved for the 128 triplet (50% gray) . However, in X11, "gray" was assigned to the 190 triplet (74.5%) , which is close to W3C "Silver" at 192 (75.3%) , and had "Light Gray" at 211 (83%) and "Dark Gray" at 169 (66%) counterparts. As a result, the combined CSS 3.0 color list that prevails on the web today produces "Dark Gray" as a significantly lighter tone than plain "Gray" , because "Dark Gray" was descended from X11 – for it did not exist in HTML nor CSS level 1 – while "Gray" was descended from HTML. Even in the current draft for CSS 4.0, dark gray continues to be a lighter shade than gray. Some browsers such as Netscape Navigator insisted on an "a" in any "Gr''a''y" except for "Light Gr''e''y". Recent X releases (since 2014, xorg-rgb version 1.0.6) also support the W3C definitions. In X11, the original definitions have been preserved (so "Dark Gray" remains a darker shade of "Gray"), but for every conflicting name pair, "Web" and additional "X11" prefixes have been added to ease disambiguation after the merger. The "X11" prefix is an alias for the non-prefixed version, i.e. "X11 Gray" = "Gray" ≠ "Web Gray". The W3C also defined a color that is equal to X11's "Green", but called it "Lime". In X11, this is simply called "Lime", as no such name existed before. It aliases to "Green", i.e. "Lime" = "Green" = "X11 Green" ≠ "Web Green".

Color name chart

The following chart presents the standardized X11 color names from the X.org source code. The list of names accepted by browsers following W3C standards slightly differs as explained above. The table does not show numbered gray and brightness variants as described below. Actual rgb.txt files and other color databases or palettes may differ since they are freely editable by vendors and users. The table shows component values in several notations of the

RGB The RGB color model is an additive color model in which the red, green, and blue primary colors of light are added together in various ways to reproduce a broad array of colors. The name of the model comes from the initials of the three ...

color space, with conversions to

HSL and HSV HSL and HSV are the two most common cylindrical coordinate system, cylindrical-coordinate representations of points in an RGB color model. The two representations rearrange the geometry of RGB in an attempt to be more intuitive and color vision, ...

assuming

sRGB sRGB (standard RGB) is a colorspace, for use on monitors, printers, and the World Wide Web. It was initially proposed by HP and Microsoft in 1996 and became an official standard of the International Electrotechnical Commission (IEC) as IEC 6 ...

color space.

Color variations

Shades of gray

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 Gray''N'' := round(''N''% × 255) resulting in e.g. 'Gray96' , which happens to be the same as 'White Smoke'. Similarly 'Dim Gray' is the same as 'Gray41' . On the other hand, 'Gray' lies between 'Gray74' and 'Gray75' ; 'Dark Gray' is not the same as 'Gray66' ; and 'Light Gray' is not the same as 'Gray83' . These shades are not included in W3C specifications, although drafts for level 4 of the CSS Color module include a similar function gray(). They are still coded without 'Grey' alternatives, but with no space before the digit.

Numbered variants

For 78 colors (not counting grays), rgb.txt offers four variants "''color''1", "''color''2", "''color''3", and "''color''4", with "''color''1" sometimes corresponding to "''color''", so e.g. "Snow1" is the same as "Snow". Unlike base colors, e.g. cadet blue and CadetBlue, these are only coded without spaces, e.g. CadetBlue3. These variations are neither supported by popular browsers nor adopted by W3C standards. Whether or not a certain color has such variants seems random. If "''color''1" is not the same as "''color'', the base color is usually darker. That means its brightness in HSB color notation is less than 100%; about 30 of the base colors are fully bright. The four variants (1...4) have rounded brightness values of 100%, 93%, 80% and 55%, respectively. Their hue and saturation are usually the same except for rounding. In some cases they differ from the base color, though, which may indicate that these variants were specified with alternate definitions of the bases in mind, i.e. their values were adapted to a certain monitor which was commonly done by vendors until the 1990s. The fixed brightness settings correspond closely to these formulae to determine the RGB values: ''color''1 := ''color'' × 100% ''color''2 := ''color''1 × 93.2% ''color''3 := ''color''1 × 80.4% ''color''4 := ''color''1 × 54.8% Examples: * "Yellow 2" (238, 238, 0) is based on "Yellow" (255, 255, 0) with 255 × 0.932 = 237.66. * "Ivory 3" (205, 205, 193) is explained by "Ivory" (255, 255, 240) where 255 × 0.804 = 205.02 and 240 × 0.804 = 192.96. * "Azure 4" (131, 139, 139) is close to "Azure" (240, 255, 255) values transformed as 255 × 0.548 = 139.74 and 240 × 0.548 = 131.52.

Prefixed variants

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. Several sets, however, feature a ''Dark'' variant with 55% brightness and some have their ''Medium'' at about 80%. "Light Goldenrod Yellow" and "Dark Olive Green" are special, because there are no corresponding color entries without ''Dark'' and ''Light'' prefixes.

Nuances with different hue

Several groups of colors share the same lightness or brightness and saturation. These ''nuances'' differ only by hue. ; 100%/25%: 0° (Web) Maroon, 60° Olive, 120° Green, 180° Teal, 240° Navy (Blue), 300° (Web) Purple ; 100%/27%: 0° Dark Red, 180° Dark Cyan, 240° Dark Blue, 300° Dark Magenta ; 100%/41%: 181° Dark Turquoise, 282° Dark Violet ; 100%/49%: 90° Lawn Green, 157° Medium Spring Green ; 61%/50%: 80° Yellow Green, 120° Lime Green, 280° Dark Orchid ; 100%/50%: 0° Red, 16° Orange Red, 33° Dark Orange, 39° Orange, 51° Gold, 60° Yellow, 90° Chartreuse, 120° (Lime) Green, 150° Spring Green, 180° Aqua / Cyan, 195° Deep Sky Blue, 240° Blue, 300° Fuchsia / Magenta ; 25%/65%: 0° Rosy Brown, 120° Dark Sea Green ; 59–60%/65%: 260° Medium Purple, 302° Orchid, 340° Pale Violet Red ; 100%/86%: 38° Moccasin, 351° Light Pink ; 100%/90%: 36° Blanched Almond, 54° Lemon Chiffon ; 67%/94%: 30° Linen, 240° Lavender ; 100%/94%: 6° Misty Rose, 60° Light Yellow, 180° Light Cyan ; 100%/97%: 25° Seashell, 40° Floral White, 60° Ivory, 120° Honeydew, 180° Azure, 208° Alice Blue, 340° Lavender Blush ; 100%/99%: 0° Snow, 240° Ghost White

Tints and shades with different lightness

Several groups of colors share the same hue and HSL saturation. ''Tints'' are lighter than a base color, ''shades'' are darker. ; 0°/0%: 0% Black, 41% Dim Gray, 50% (Web) Gray, 66% Dark Gray, 75% (X11) Gray, 75% Silver, 83% Light Gray, 86% Gainsboro, 96% White Smoke, 100% White ; 0°/100%: 25% (Web) Maroon, 27% Dark Red, 50% Red, 99% Snow ; 16°/100%: 50% Orange Red, 66% Coral ; 33°/100%: 50% Dark Orange, 88% Bisque ; 36°/100%: 84% Navajo White, 90% Blanched Almond ; 60°/100%: 25% Olive, 50% Yellow, 94% Light Yellow, 97% Ivory ; 80°/61%: 35% Olive Drab, 50% Yellow Green ; 90°/100%: 49% Lawn Green, 50% Chartreuse ; 120°/61%: 34% Forest Green, 50% Lime Green ; 120°/100%: 20% Dark Green, 25% (Web) Green, 50% (X11) Green / Lime, 97% Honeydew ; 146–147°/50%: 36% Sea Green, 47% Medium Sea Green ; 150°/100%: 50% Spring Green, 98% Mint Cream ; 180–181°/100%: 25% Teal, 27% Dark Cyan, 41% Dark Turquoise, 50% Aqua / Cyan, 94% Light Cyan, 97% Azure ; 240°/100%: 25% Navy Blue, 27% Dark Blue, 40% Medium Blue, 50% Blue, 99% Ghost White ; 300°/100%: 25% (Web) Purple, 27% Dark Magenta, 50% Fuchsia / Magenta ; 328–330°/100%: 54% Deep Pink, 71% Hot Pink ; 350–351°/100%: 88% Pink, 86% Light Pink

Tones with different saturation

Some pairs of colors share the same lightness and hue. These ''tones'' differ only by saturation. Tones are far less common in the X11 set than nuances, tints and shades. ; 0°/41%: 0% Dim Gray, 59% Brown ; 120°/50%: 61% Lime Green, 100% Green / Lime ; 180°/25%: 25% Dark Slate Gray, 100% Teal ; 240°/27%: 64% Midnight Blue, 100% Dark Blue

Derived lists

The Printer Working Group (PWG) of the

IEEE The Institute of Electrical and Electronics Engineers (IEEE) is an American 501(c)(3) organization, 501(c)(3) public charity professional organization for electrical engineering, electronics engineering, and other related disciplines. The IEEE ...

publishes a standard
PWG 5101.1
whose mandatory color names are based upon RFC 3805, successor to RFC 1759 which imported the functional color names ''other'', ''unknown'' and ''transparent'' alongside seven basic colors from ISO 10175 ( DPA) and ISO 10180 ( SPDL), and JTAPI. This standard has four variants for each non-monochromatic color: ''clear'' (50% transparent), ''dark'', ''light'' and the default. Wherever possible, the values are the same as in the W3C adaptation of the X11 list, except for Turquoise which is instead of . Missing variant values have been added systematically. ''Buff'' and ''Mustard'' are completely new color names. Light Black and Gray correspond to the same color.

References

External links

X-Server source code with built-in colors

"Extended Color Keywords", ''CSS Color Module Level 3''
a W3C Recommendation
X11 rgb.txt 1.1
at Xfree.86.org, 1994
X11 rgb.txt 1.2
2005 (excluding 96 aliases); an
Modern X.Org rgb.txt
from GitHub. * Aubrey Jaffer
"Color-Name Dictionaries"
Jaffer's page includes extensive information about and comparisons between color-name dictionaries.
.NET Framework and Windows Forms color names
{{Color shades Color names X Window System Cascading Style Sheets