Color Contrast Analyzer

New in version 1.1: Download the image analysis to a PNG file.

This extension allows you to analyze text color contrast problems on a webpage according to the WCAG 2 text color contrast requirements. It evaluates the page as it appears in the browser, so it is able to handle text over gradients and advanced CSS attributes. You can choose to analyze a portion of a web page, the entire visible contents of a tab, or an entire web page.

Additionally, you can evaluate files on your computer that can be opened in Chrome, such as image files and PDF files. Note, with PDF files you will only be able to evaluate the visible portion of the page. To analyze local files you will need to go to your Extensions page and check "Allow access to file URLs" for this extension.

You can select to evaluate for either AA or AAA conformance, along with specifying the size of the text you want to analyze.

The output will show you a map of where the edges between colors are different enough to meet the specified contrast requirement. If there is an item on the underlying page that is not outlined in the output mask, then the item does not have enough color contrast according to the conformance level you selected. The resulting image analysis can be downloaded to your computer as a PNG file.

In order to better handle gradients, you can also select the pixel radius that should be used to analyze adjacent pixels. The larger the pixel radius, the further out it will look for a border with high enough contrast. However, a larger pixel radius will add significant computation time.

When first installing the extension, you may need to refresh the webpage you wish to analyze for all of the selection options to be available.

Also, when installing the extension it will ask you for permission to access your data on all of your websites and your tabs and browsing activity. We are not using or collecting this data in any way. In order to get permission to take screenshots of your browser window this is the level of access we must request. You can view the source code at the following URL.

https://github.com/gdkraus/color-contrast-chrome

This tool is a product of the IT Accessibility Office at NC State University.

http://accessibility.oit.ncsu.edu/