A number of colors are defined by web browsers.  Some browsers such as Netscape Navigator insisted on an "a" in any "Gray" except for "Light Grey". CadetBlue3. A color tool or other graphics software is often used to generate color values. Web colors have an unambiguous colorimetric definition, sRGB, which relates the chromaticities of a particular phosphor set, a given transfer curve, adaptive whitepoint, and viewing conditions. It aliases to "Green", i.e. Despite this, graphic designers and others got used to them, making it practically impossible to introduce a different list. 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. The project was running DEC VT240 terminals at the time, so would have worked to that device.. RGB values are usually given in the 0–255 range; if they are in the 0–1 range, the values are multiplied by 255 before conversion. The first versions of Mosaic and Netscape Navigator used the X11 colors as the basis for the web colors list, as both were originally X applications. This number divided by sixteen (integer division; ignoring any remainder) gives the first hexadecimal digit (between 0 and F, where the letters A to F represent the numbers 10 to 15.  The CSS3 color module has deprecated the use of system colors in favor of CSS3 UI System Appearance property, which itself was subsequently dropped from CSS3. Whether or not a certain color has such variants seems random. , Color names are not standardized by Xlib or the X11 protocol. The number of colors that can be represented by this system is 166 or 2563 or 224 = 16,777,216. "Remove all traces of external RGB database (and Speedo)", "~alanc/xc-historical - Partial/incomplete import of X consortium historical RCS up to X11R6.0", "Last call comments on CSS3 module: color", X-Server source code with built-in colors, https://en.wikipedia.org/w/index.php?title=X11_color_names&oldid=982069294, Short description is different from Wikidata, Creative Commons Attribution-ShareAlike License, This page was last edited on 6 October 2020, at 00:28. A hex triplet is a six-digit, three-byte hexadecimal number used in HTML, CSS, SVG, and other computing applications to represent colors.  The working draft for the CSS4 color module combines the Basic and Extended sections together in a simple "Named Colors" section. 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.  Blooberry.com notes that Opera 2.1 and Safari 1 also included Netscape's expanded list of 140 color names, but later discovered 14 names not included with Opera 3.5 on Windows 98. If "color1" is not the same as "color", the base color is usually darker.  The optional module xorg/app/rgb contains the stand-alone rgb.txt file. These colors were chosen specifically because they matched the palettes selected by various browser applications. Several groups of colors share the same lightness or brightness and saturation. Recent W3C specifications of color names distinguishes between basic and extended colors.. Even in the current draft for CSS 4.0, dark gray continues to be a lighter shade than gray. cadet blue and CadetBlue, these are only coded without spaces, e.g. 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' . their values were adapted to a certain monitor which was commonly done by vendors until the 1990s. Wherever possible, the values are the same as in the W3C adaptation of the X11 list, except for Turquoise which is instead of . There were not very different palettes in use in different browsers. For instance the RGB value 201 divides into 12 groups of 16, thus the first digit is C. A remainder of nine gives the hexadecimal number C9. The table does not show numbered gray and brightness variants as described below. It is one of the three primary colors used in the RGB color space along with red and blue. Recent X releases also support the W3C definitions. In computing, on the X Window System, X11 color names are represented in a simple text file, which maps certain strings to RGB color values. Light Black and Gray correspond to the same color. Actual rgb.txt files and other color databases or palettes may differ since they are freely editable by vendors and users. The following chart presents the standardized X11 color names from the X.org source code. Wikimedia list article about CSS, color, and the X11 system, Clashes between web and X11 colors in the CSS color scheme, Tints and shades with different lightness. The first versions of Mosaic and Netscape Navigator used the X11 colors as the basis for the web colors list, as both were originally X applications. Their hue and saturation are usually the same except for rounding. The three additive primaries … X11 colors are defined as simple RGB (hence, no particular color space), rather than sRGB. The W3C specifications SVG and CSS level 3 module Color eventually adopted the X11 list with some changes. The Printer Working Group (PWG) of 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. , In CSS 2.1, the color 'orange' (one of the 140) was added to the section with the 16 HTML4 colors as a 17th color. The "X11" prefix is an alias for the non-prefixed version, i.e. The bytes represent the red, green and blue components of the color. The W3C 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 colors” defined in HTML 3.2 and CSS level 1. A particular browser may not recognize all of these colors, but as of 2005, all modern, general-use, graphical browsers support the full list of colors. "X11 Gray" = "Gray" ≠ "Web Gray". Buff and Mustard are completely new color names. The present W3C list is a superset of the 16 “VGA colors” defined in HTML 3.2 and CSS level 1. The remainder gives the second hexadecimal digit. The hex triplet is formed by concatenating three bytes in hexadecimal notation, in the following order: For example, consider the color where the red/green/blue values are decimal numbers: red=36, green=104, blue=160 (a grayish-blue color). X11 color names, HTML/CSS: ISCC–NBS descriptor: Vivid yellowish green: B: Normalized to [0–255] (byte) The color defined as green in the RGB color model, displayed on the right, is the brightest possible green that can be reproduced on a computer screen, and is the color named green in X11. The complete rgb.txt defines 101 shades from 'Gray0' (black) up to 'Gray100' (white) in addition to 'Gray' and its variants listed above. User agents vary in the fidelity with which they represent the specified colors. The list of colors shipped with the X11 product varies between implementations and clashes with certain of the HTML names such as green. They are not part of SVG Tiny.  The list of names accepted by browsers following W3C standards slightly differs as explained above. 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.  Specifying a non-sRGB color this way requires the RGB() function call; it is impossible with the hexadecimal syntax (and thus impossible in legacy HTML documents that do not use CSS). One shortcoming of the web-safe palette is its small range of light colors for webpage backgrounds, whereas the intensities at the low end of the range, such as the two darkest, are similar to each other, making them hard to distinguish. In some uses, hexadecimal color codes are specified with notation using a leading number sign (#). The decimal numbers 36, 104 and 160 are equivalent to the hexadecimal numbers 24, 68 and A0 respectively. The shades are apparently defined by the formula GrayN := round(N% × 255) resulting in e.g. David Lehn and Hadley Stern discovered that only 22 of the 216 colors in the web-safe palette are reliably displayed without inconsistent remapping on 16-bit computer displays. The list does not show continuity either in selected color values or in color names, and some color triplets have multiple names. , CSS also supports the special color transparent, which represents an alpha value of zero; by default, transparent is rendered as an invisible nominal black: rgba(0, 0, 0, 0).. 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). Digital Color Imaging Handbook By Gaurav Sharma. The list of colors is presented as if it had special properties that render them immune to dithering, but on 256-color displays applications can actually set a palette of any selection of colors that they choose, dithering the rest. ", The extended colors is the result of merging specifications from HTML 4.01, CSS 2.0, SVG 1.0 and CSS3 User Interfaces (CSS3 UI).. They called these 22 colors "the reallysafe palette"; it consists largely of shades of green, yellow, and blue, as can be seen in the table below. Changes", "CSS Color Module Level 3 – Working Draft", CSS Color Module Level 4 – Editor’s Draft, 26 June 2014, "CSS3 Basic User Interface Module, W3C Candidate Recommendation 11 May 2004: System Appearance", "Re: [CfC] adding 'rebeccapurple' to CSS Color Level 4", Optimal Colors to Improve Readability for People with Dyslexia, Linguistic relativity and the color naming debate, International Commission on Illumination (CIE), https://en.wikipedia.org/w/index.php?title=Web_colors&oldid=991007047, All Wikipedia articles written in American English, Articles with unsourced statements from May 2011, Articles prone to spam from September 2013, Creative Commons Attribution-ShareAlike License, This page was last edited on 27 November 2020, at 19:40. , CSS 2, SVG and CSS 2.1 allow web authors to use system colors, which are color names whose values are taken from the operating system, picking the operating system's highlighted text color, or the background color for tooltip controls. The web colors list is descended from it but differs for certain color names. Conversion between number bases is a common feature of calculators, including both hand-held models and the software calculators bundled with most modern operating systems. , The list of web "X11 colors" from the CSS3 specification, along with their hexadecimal and decimal equivalents, is shown below. Many of these colors are from the list of X11 color names distributed with the X Window System. 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. "HTML 4.01 Specification section 6.5 "Colors, "HTML 3.2 Specification "The BODY element, "W3C TR SVG 1.0, recognized color keyword names", "Web Color Reference - HTML with Style | 4 | WebReference", "CSS 2.1 Specification: Syntax and basic data types: Colors", "CSS Color Module Level 3 – Proposed Recommendation - 11. Colors may be specified as an RGB triplet or in hexadecimal format (a hex triplet) or according to their common English names in some cases. Web colors ; White: silver: grey: black: blue: teal: cyan: green olive: yellow: orange: brown: orange-red: red: maroon: pink: magenta: … The first versions of Mosaic and Netscape Navigator used the X11 color names as the basis for their color lists, as both started as X Window System applications. The list of colors shipped with the X11 product varies between implementations and clashes with certain of the HTML names such as green. This limitation is sufficient for many text based documents. Unlike base colors, e.g. For 78 colors (not counting grays), rgb.txt offers four variants "color1", "color2", "color3", and "color4", with "color1" sometimes corresponding to "color", so e.g. In X11, this is simply called "Lime", as no such name existed before. Notice that the colors named in the report use different color values than the web colors of the same name. Enhanced accessibility requires contrast ratios greater than 7:1. Either no colors should be specified (to invoke the browser's default colors), or both the background and all foreground colors (such as the colors of plain text, unvisited links, hovered links, active links, and visited links) should be specified to avoid black on black or white on white effects.. The recommendations they refer to of off-black (0x0A0A0A) on off-white (0xFFFFE5) and black (0x000000) on creme (0xFAFAC8) have contrast ratios of 11.7:1 and 20.3:1 respectively. This can be done by either using the closest color, or by using dithering. The Web Content Accessibility Guidelines recommend a contrast ratio of at least 4.5:1 between the relative luminance of text and its background color or at least 3:1 for large text. They are still coded without 'Grey' alternatives, but with no space before the digit. "Web-safe" colors had a flaw in that, on systems such as X11 where the palette is shared between applications, smaller color cubes (5×5×5 or 4×4×4) were allocated by browsers—the "web safe" colors would dither on such systems. The hex triplet is obtained by concatenating the six hexadecimal digits together, 2468A0 in this example. 'Gray96' , which happens to be the same as 'White Smoke'. Colors outside the sRGB gamut can be specified in Cascading Style Sheets by making one or more of the red, green and blue components negative or greater than 100%, so the color space is theoretically an unbounded extrapolation of sRGB similar to scRGB. 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.  These have been chosen to be similar to many real-world monitors and viewing conditions, in order to allow rendering to be fairly close to the specified values even without color management. Tones are far less common in the X11 set than nuances, tints and shades. The table shows component values in several notations of the RGB color space, i.e. 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.. This means that the list of colors found in X11 (e.g., in /usr/lib/X11/rgb.txt) should not directly be used to choose colors for the web. Some pairs of colors share the same lightness and hue.  These may be dictated by the hardware or changeable by a "color table". This represents the least (0) to the most (255) intensity of each of the color components. Some browsers and devices do not support colors. , The Cascading Style Sheets specification defines the same number of named colors as the HTML 4 spec, namely the 16 html colors, and 124 colors from the Netscape X11 color list for a total of 140 names that were recognized by Internet Explorer (IE) 3.0 and Netscape Navigator 3.0. each color code listed is a shorthand for the RGB value; for example, code 609 is equivalent to RGB code 102-0-153 or HEX code #660099, Designers were encouraged to stick to these 216 "web-safe" colors in their websites because there were a lot of 8-bit color displays when the 216-color palette was developed. Similarly 'Dim Gray' is the same as 'Gray41' . Web-based tools specifically for converting color values are also available. Thus web colors specify colors in the 24-bit RGB color scheme. These colors were standardized by SVG 1.0, and are accepted by SVG Full user agents. This includes the common synonyms: aqua (HTML4/CSS 1.0 standard name) and cyan (common sRGB name), magenta (common sRGB name) and fuchsia (HTML4/CSS 1.0 standard name), gray (HTML4/CSS 1.0 standard name) and grey.. These shades are not included in W3C specifications, although drafts for level 4 of the CSS Color module include a similar function gray(). In some applications multipart names are written with spaces, in others joined together, often in camel case. Several groups of colors share the same hue and HSL saturation. Different results were obtained by providing an image with a larger range of colors and allowing the browser to quantize the color space if needed, rather than suffer the quality loss of a double quantization. "Lime" = "Green" = "X11 Green" ≠ "Web Green". The "web-safe" colors do not all have standard names, but each can be specified by an RGB triplet: each component (red, green, and blue) takes one of the six values from the following table (out of the 256 possible values available for each component in full 24-bit color). The W3C also defined a color that is equal to X11's "Green", but called it "Lime". For these displays, or for blind and colorblind users, Web content depending on colors can be unusable or difficult to use. These nuances differ only by hue.  The CSS3.0 specification did not include orange in the "HTML4 color keywords" section, which was renamed as "Basic color keywords". That means its brightness in HSB color notation is less than 100%; about 30 of the base colors are fully bright. See hexadecimal for more details). /* RGB with alpha channel, added to CSS3 */. "Light Goldenrod Yellow" and "Dark Olive Green" are special, because there are no corresponding color entries without Dark and Light prefixes. Rich maroon [ maroon (X11) ] Color coordinates; Hex triplet: #B03060: sRGB B (r, g, b) (176, 48, 96) HSV (h, s, v) (338°, 73%, 69%) Source: X11 color names#Color name clashes: ISCC–NBS descriptor: Strong red: B: Normalized to [0–255] (byte) However, addressing accessibility concerns is not simply a matter of increasing the contrast ratio. In HTML, "Gray" is specifically reserved for the 128 triplet (50% gray) . Values flanked by "*" (asterisk) are part of the "reallysafe palette;" see Safest web colors, below. Through the 2000s, use of 256-color displays in personal computers dropped sharply in favour of 24-bit (TrueColor) displays, and the use of "web-safe" colors has fallen into practical disuse. Compare the alphabetical lists in the W3C standards. As a report to the Web Accessibility Initiative indicates, dyslexic readers are better served by contrast ratios below the maximum. The following table shows all of the "web-safe" colors. Perhaps most unusual of the color clashes between X11 and W3C is the case of "Gray" and its variants. This chart shows selected HTML and X11 colors as well as selected unofficial consensus web colors developed by web designers since 2002. This process is repeated for each of the three color values.  This standard has four variants for each non-monochromatic color: clear (50% transparent), dark, light and the default. The fixed brightness settings correspond closely to these formulae to determine the RGB values: 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. The basic colors are 16 colors defined in the HTML 4.01 specification, ratified in 1999, as follows (names are defined in this context to be case-insensitive): These 16 were labelled as sRGB and included in the HTML 3.0 specification, which noted they were "the standard 16 colors supported with the Windows VGA palette. RGB, HSL and HSV, conversions are done assuming sRGB color space. More advanced user agents use color management to provide better color fidelity; this is particularly important for Web-to-print applications. These variations are neither supported by popular browsers nor adopted by W3C standards.  In the same reference, the "SVG color keywords" section, was renamed "Extended color keywords", after starting out as "X11 color keywords" in an earlier working draft.  A color is specified according to the intensity of its red, green and blue components, each represented by eight bits. When a color is found (e.g., in an image) that is not one available, a different one had to be used. . X11 colors are defined as simple RGB (hence, no particular color space), rather than sRGB. One byte represents a number in the range 00 to FF (in hexadecimal notation), or 0 to 255 in decimal notation. Missing variant values have been added systematically. For example, the decimal triplet 4, 8, 16 would be represented by the hex digits 04, 08, 10, forming the hex triplet 040810. An abbreviated, three (hexadecimal)-digit form is used. 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. Thus, there are 24 bits used to specify a web color within the sRGB gamut, and 16,777,216 colors that may be so specified. This means that the list of colors found in X11 (e.g., in /usr/lib/X11/rgb.txt) should not directly be used to choose colors for the web. When entering code using the unofficial colors, the hex code of the color must be specified instead of writing the name of the color. In the mid-1990s, many displays were only capable of displaying 256 colors.  Expanding this form to the six-digit form is as simple as doubling each digit: 09C becomes 0099CC as presented on the following CSS example: This shorthand form reduces the palette to 4,096 colors, equivalent of 12-bit color as opposed to 24-bit color using the whole six-digit form (16,777,216 colors). Tints are lighter than a base color, shades are darker. This enables web authors to style their content in line with the operating system of the user agent. These tones differ only by saturation. Web colors are colors used in displaying web pages on the World Wide Web, and the methods for describing and specifying those colors. The four variants (1…4) have rounded brightness values of 100%, 93%, 80% and 55%, respectively. The list first shipped with X10 release 3 (X10R3) on 7 June 1986, having been checked into RCS by Jim Gettys in 1985. There were various attempts to make a "standard" color palette. It was traditionally shipped with every X11 installation, hence the name, and is usually located in /lib/X11/rgb.txt. Among their other color pairs, brown (0x282800) on dark green (0xA0A000) has a contrast ratio of 3.24:1, which is less than the WCAG recommendation, dark brown (0x1E1E00) on light green (0xB9B900) has a contrast ratio of 4.54:1 and blue (0x00007D) on yellow (0xFFFF00) has a contrast ratio of 11.4:1. The original W3C names, as used in HTML4/CSS2, before the adoption of the non-colliding X11 names as alternatives. , The developing CSS3 specification also introduces HSL color space values to style sheets:, On 21 June 2014, the CSS WG added the color RebeccaPurple to the Editor's Draft of the CSS4 Colors module, to commemorate Eric Meyer's daughter Rebecca who died on 7 June 2014, her sixth birthday. Several sets, however, feature a Dark variant with 55% brightness and some have their Medium at about 80%.