X11 color names
A set of colour names and values used in the X Window System and early web browsers
X11 color names are a collection of colour names mapped to RGB values, first shipped with the X Window System in 1986. These names, stored in a simple text file called rgb.txt, became the basis for many early web colours and are still referenced in graphics and software today, despite inconsistencies and overlaps.
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- First shipped with X Window System in 1986
- Basis for many early web colour names
- Includes over 100 shades of gray
- Names and values stored in rgb.txt file
- Not all names are standardised or unique
What colour is X11 color names?
X11 color names are a set of names linked to specific RGB colour values, used mainly in computer graphics and software. The list includes a wide range of colours, from basic shades like Red and Blue to many nuanced variants such as Light Goldenrod Yellow and Dark Olive Green. Some colours have multiple names or aliases, and not all names are consistent across different systems. The list is known for its practical use in digital environments rather than for any artistic or chemical origin.
Where does X11 color names come from?
The X11 color names originated with the X Window System, a graphical interface for Unix systems. The list was first included in X10 release 3 in 1986, with contributions from several developers who drew on paint samples and crayon sets. The names and values were stored in a file called rgb.txt. Over time, the list influenced web colour standards, though there are differences between X11 and W3C definitions.
How X11 color names is defined
The colours are defined by mapping names to RGB values in a plain text file, originally rgb.txt. Each entry assigns a name to a specific combination of red, green, and blue values. The system allows for both named colours and numbered variants, such as Gray0 through Gray100, calculated by formula. The list is now built into X server software rather than shipped as a separate file.
Where X11 color names is used
X11 color names are used in computer graphics, especially in the X Window System and early web browsers like Mosaic and Netscape Navigator. They provide a standard set of colour names for use in software, web design, and digital art. Some applications and programming languages still reference these names for compatibility and convenience.
Orange around the world
What the orange family means from country to country.
The lowest band of the flag is orange, often called apricot, after the national fruit. The constitution says it stands for the creative talent and hard work of the people.
Politics and protestNature and renewalPrideSource: Flag of ArmeniaThe flag is split corner to corner. The orange half stands for the Buddhist tradition, and the white dragon across the middle for purity.
Sacred and holySource: Flag of BhutanOn 30 September people wear orange shirts to remember the children sent to residential schools. Phyllis Webstad's new orange shirt was taken from her on her first day at one.
Mourning and deathPolitics and protestGriefSource: National Day for Truth and ReconciliationOrange is also the colour of the New Democratic Party. Its sweep of Quebec seats in the 2011 election was called the Orange Wave.
Politics and protestSource: New Democratic PartyThe flag shows the island in copper orange on white. The colour recalls copper, which was mined here in ancient times and may have taken its name from Cyprus.
Politics and protestNature and renewalSource: Flag of CyprusThe orange stripe of the flag stands for Protestants, the followers of William of Orange. In Northern Ireland the Orange Order still marches each 12 July in orange sashes.
Politics and protestSource: Orange OrderShades and relatives of X11 color names
The list includes many variants of each colour, such as numbered grays from Gray0 (black) to Gray100 (white), and brightness variants like color1 through color4. Some names have prefixes like Light, Dark, Medium, or Deep, but these are not always systematic. There are also differences between X11 and web standards, especially for colours like Gray and Green, which may refer to different RGB values depending on the context.
Colours that go with X11 color names
Harmonies are worked out from the value #FFEBCD. Contrast ratios follow the WCAG 2 formula.
Questions people ask about X11 color names
What are X11 color names?
X11 color names are a set of names assigned to specific RGB colour values, originally used in the X Window System for Unix computers. They are stored in a file called rgb.txt and are widely used in software and web design.
Where does the name 'X11 color names' come from?
The name comes from the X Window System, version 11 (X11), where these colour names and values were first standardised and distributed in a file called rgb.txt.
How are X11 colors defined?
Each X11 colour is defined by a name and an RGB value, listed in a text file. Some colours have multiple names or numbered variants, and the list includes both basic and nuanced shades.
Are X11 color names the same as web colors?
Many early web colours were based on the X11 list, but there are differences. For example, 'Gray' and 'Green' refer to different RGB values in X11 and web standards.
Why are there so many shades of gray in X11?
The rgb.txt file defines 101 shades of gray, from Gray0 (black) to Gray100 (white), using a formula to calculate each value. This provides a wide range of gray tones for use in digital graphics.
Good reading and sources
The facts on this page come from the Wikipedia article "X11 color names", written by its contributors and used under the CC BY-SA 4.0 licence, and from its Wikidata record (CC0). Rang rewrote the text in its own words, with AI assistance, and compares every page with the article to make sure no passage is copied. It may be reused under the same CC BY-SA 4.0 licence with a link back.
It may contain mistakes. The swatch is an approximation: named colours are not fixed standards, and every screen shows them a little differently. If something is wrong, tell us. Last refreshed 2026-10-03.
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