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. Several groups of colors share the same hue and HSL saturation. 'Gray96' , which happens to be the same as 'White Smoke'.  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. Perhaps most unusual of the color clashes between X11 and W3C is the case of "Gray" and its variants.  A color is specified according to the intensity of its red, green and blue components, each represented by eight bits. 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. their values were adapted to a certain monitor which was commonly done by vendors until the 1990s. 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. 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. This limitation is sufficient for many text based documents. An abbreviated, three (hexadecimal)-digit form is used. The shades are apparently defined by the formula GrayN := round(N% × 255) resulting in e.g. X11 colors are defined as simple RGB (hence, no particular color space), rather than sRGB. For example, the decimal triplet 4, 8, 16 would be represented by the hex digits 04, 08, 10, forming the hex triplet 040810. , 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. This can be done by either using the closest color, or by using dithering. The complete rgb.txt defines 101 shades from 'Gray0' (black) up to 'Gray100' (white) in addition to 'Gray' and its variants listed above. More advanced user agents use color management to provide better color fidelity; this is particularly important for Web-to-print applications. The table shows component values in several notations of the RGB color space, i.e. X11 colors are defined as simple RGB (hence, no particular color space), rather than sRGB. 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 following table shows all of the "web-safe" colors. These shades are not included in W3C specifications, although drafts for level 4 of the CSS Color module include a similar function gray(). , The list of web "X11 colors" from the CSS3 specification, along with their hexadecimal and decimal equivalents, is shown below. The list does not show continuity either in selected color values or in color names, and some color triplets have multiple names. 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. 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. They are not part of SVG Tiny. A hex triplet is a six-digit, three-byte hexadecimal number used in HTML, CSS, SVG, and other computing applications to represent colors. 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. ", 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).. This enables web authors to style their content in line with the operating system of the user agent. Tints are lighter than a base color, shades are darker. The list of colors shipped with the X11 product varies between implementations and clashes with certain of the HTML names such as green. 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. 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. Despite this, graphic designers and others got used to them, making it practically impossible to introduce a different list. When entering code using the unofficial colors, the hex code of the color must be specified instead of writing the name of the color. Several sets, however, feature a Dark variant with 55% brightness and some have their Medium at about 80%.  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). 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. 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. RGB, HSL and HSV, conversions are done assuming sRGB color space.  These may be dictated by the hardware or changeable by a "color table". 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. A set of colors was needed that could be shown without dithering on 256-color displays; the number 216 was chosen partly because computer operating systems customarily reserved sixteen to twenty colors for their own use; it was also selected because it allows exactly six equally spaced shades of red, green, and blue (6 × 6 × 6 = 216), each from 00 to FF (including both limits). The table does not show numbered gray and brightness variants as described below. Even in the current draft for CSS 4.0, dark gray continues to be a lighter shade than gray. These tones differ only by saturation. Thus web colors specify colors in the 24-bit RGB color scheme. , 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).. The three additive primaries … 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. Many of these colors are from the list of X11 color names distributed with the X Window System. "Snow1" is the same as "Snow". 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. Some browsers and devices do not support colors.  This standard has four variants for each non-monochromatic color: clear (50% transparent), dark, light and the default.  The CSS3.0 specification did not include orange in the "HTML4 color keywords" section, which was renamed as "Basic color keywords". Actual rgb.txt files and other color databases or palettes may differ since they are freely editable by vendors and users. There were not very different palettes in use in different browsers. 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.. In the mid-1990s, many displays were only capable of displaying 256 colors.