Vischeck is a program that shows what a web page or image looks like to a person who is colorblind. It was created at Stanford University drawing on algorithms developed at visual laboratories around the world.
Use Vischeck - external link online or downloaded for free. From this site, users may run their own images or web pages through this program by selecting Run Images or Run Webpages from the left-hand menu.
Using Vischeck for Accessibility Evaluation
Testing a web page
Developers can view web pages by using the Vischeck simulation - external link. Simply select the color deficiency to be simulated, enter the URL of the web page you want tested and select the Run Vischeck! button. The results take some time to display.
Web developers can use this Vischeck function to make certain that the colors of text or graphics within a document do not have important content- or functionality- related meaning that may affect the accessibility of the web page.
Testing an image
You can view images - external link using the Vischeck simulation. Browse your local hard drive for the image file you would like to test, and select the color deficiency to be simulated. Vischeck will display the adjusted image next to your original image so you can compare the results. You may choose to test the same image simulating a different color-deficiency or test a different image.
Web developers can use this to make certain that there is no message in their image that is communicated solely by color. There is also a Photoshop plugin available that will allow you to analyze the image directly within Photoshop.
Again, failure to be aware of important content or functionality that is color-related can affect the accessibility of the web page, not only for people with disabilities, but also for people who use hardware that may not support color.