Making sure your documents follow guidelines for optimum contrast is helpful for all students but especially for those with visual impairments like color blindness. Good contrast makes content easier to view when it’s projected in class or on low-quality monitors. It also makes viewing content easier on a mobile device any time there’s a glare on the screen. If you are using Ally to address accessibility issues in your course site, you have likely come across Ally’s recommendation to use the Colour Contrast Analyser tool to check your files for acceptable contrast.

TPGi’s Colour Contrast Analyser tool can help you check the color contrast of documents, images, and webpages, and is free for download. Based on WCAG 2.1 guidelines for contrast, the tool enables you to select background and foreground colors from your computer display to determine if the color combination meets minimum guidelines.

How to download and install the free Colour Contrast Analyser

1. Go to TPGi’s Color Contrast Analyser Resources page.
2. Click the Download TPGi Color Contrast Analyser Now button.
   
3. If prompted to do so, select where you'd like the setup file to be downloaded and saved on your device.
4. Once the setup file is downloaded, find it in your computer’s default location for downloads (or the folder you selected when prompted) and double-click the file to install the program on your computer.

How to use the free Colour Contrast Analyser

Once installed, you’ll see the Colour Contrast Analyser program icon on your desktop. Double-click the icon to launch the program. A floating window will appear, and you will see an eyedropper icon in the area labeled "Foreground" and another in the area labeled "Background." Click the eyedropper icon to hover over an area of your screen and select a foreground color. Repeat the process to select a background color. The tool will then let you know if the contrast between the two selected colors is within an acceptable range.

NOTE: The Colour Contrast Analyser tool works best on a “native” display. If you are extending your screen to multiple monitors or from a laptop to an external monitor, you may experience issues with the selection tool. We recommend moving open windows to the built-in display when you use the Colour Contrast Analyser tool.

Contrast Ratio

After you’ve selected your colors with the tool, you will notice a contrast ratio listed in the floating window. If you would like more information on how to use contrast ratios to determine accessibility, we recommend WebAIM’s Contrast and Color Accessibility article.