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Accessibility > Web Content > Assessment Tools > Color and Contrast
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Color and Contrast

AccessColor External Resource
AccessColor is a free online tool which analyzes the internal and external CSS of a web page to test the color contrast and color brightness between the text and background colors. It uses the algorithm recommended by the W3C at http://www.w3.org/TR/AERT#color-contrast.
Accessibility color wheel External Resource
A tool that helps in the choice of a color pair (text/background) to use in a web page. It simulates three kinds of color blindness and it shows the result of w3c algorithms, that compute contrast and difference of brightness, applied to the chosen colors. The accessibility color wheel shows if the color pair is "good" from an accessibility point of view.
Color Blindness Check External Resource
Color Blind Check is a little tool for people to test their WebPages with. It re-colorizes any webpage you like into a palette that closely resembles the typical palette available to a person having a red/green color vision deficiency (It approximates to Protanopia).
Color Blindness Simulator External Resource
One in twenty people have some form of color vision deficiency. Etre's Color Blindness Simulator allows you to upload an image to experience it as color blind users may.
Color Check External Resource
Etre's Color Check determines the color difference and contrast between any two colors to maximize readability.
Color Contrast Analyzer External Resource
It is primarily a tool for checking foreground & background color combinations to determine if they provide good color visibility. It also contains functionality to create simulations of certain visual conditions such as color blindness. Determining "colour visibility" is based on two sets of algorithms: Luminosity Contrast Ratio and Color Difference and Brightness Difference, suggested by the World Wide Web Consortium (W3C).
Color Contrast Analyzer External Resource
The Color Contrast Analyzer is a tool for checking foreground & background color combinations to determine if they provide good color visibility for conformance with Checkpoint 2.2 of the Web Content Accessibility Guidelines 1.0. It determines color visibility based on algorithms suggested by the W3C - Two colors are considered to provide good color visibility if the brightness difference and the color difference between the two colors are greater than a set range. In addition to analyzing contrast for normal vision it also calculates results for three types of color blindness (Protanopia, Deuteranopia and Tritanopia).
Color Filter External Resource
Several filters to manipulate images and other file types to see how they may appear for other users.
Color Laboratory External Resource
This color laboratory allows you to select colors and see how they appear next to one another, and in various foreground/background combinations. It also allows you to see those colors as they might appear to color-blind users.
ColorDoctor External Resource
ColorDoctor is a simulating program that checks accessibility from the aspect of color. It converts any images displayed on the screen such as websites including Web 2.0, and other presentation contents, into gray scale or colors that person who has color blindness perceives.
ColorSelector External Resource
ColorSelector is a program that provides a real-time evaluation of whether or not the colors of a website's texts and backgrounds are easily viewable by people with cataracts or color blindness. At the time of developing a website including Web 2.0, and other presentation contents, ColorSelector determines whether the selected color combinations of text and background are easily readable, and further it displays the most appropriate combination. In this manner, it assists in the creation of visual contents with a high level of accessibility.
Contrast Analyser for Apple MAC External Resource
the Contrast Analyser is primarily a tool for checking foreground & background colour combinations to determine if they provide good colour visibility. It also contains functionality to create simulations of certain visual conditions such as colour blindness. Determining "colour visibility" is based on the Contrast Ratio algorithm, suggested by the World Wide Web Consortium (W3C).
Foreground/Background Color Contrast Analyzer External Resource
Calculates Foreground and Background color contrast and difference per W3C algorithms. This is a web-based, platform independent tool. It requires that JavaScript is enabled in your browser.
Luminosity Contrast Ratio Analyzer External Resource
The Luminosity Contrast Ratio Analyzer (Beta) enables allow foreground and background color combinations to be tested against the suggested luminosity contrast ratio algorithm (http://juicystudio.com/article/luminositycontrastratioalgorithm.php) being considered by the W3C for WCAG 2.0.
Vischeck External 

Resource
Vischeck is a way of showing you what things look like to someone who is color blind. You can try Vischeck online - either run Vischeck on your own image files or run Vischeck on a web page. You can also download programs to let you run it on your own computer.
Visolve External Resource
Visolve is software that transforms the computer display colors into the discriminable colors for various people with color blindness. One of its aims is to help people with color blindness guess a normal color. In addition to the color transformation, it provides the following two functions: the filtering darkens all colors other than the specified color, and the hatching draws different hatch patterns depending on color.