Making Your EIT Distinguishable
“Distinguishable” means that the content you produce is easily readable by individuals with a wide variety of vision impairments as well as by the nonimpaired public at large. Visual impairments can include colorblindness, low vision, blurred vision, and more. There are four main criteria in making your EIT distinguishable. Each is addressed below.
Color as the Sole Distinguishing Characteristic
Principle: The EIT must not use color as the sole distinguishing characteristic of a piece of content.
Roughly 8 percent of men and 0.5 percent of women are affected by colorblindness (or color deficiency). Colorblindness is not simply limited to the colors red and green; it runs across a variety of colors. As such, you cannot assume that any single individual can see a particular color as the color you expect.
Accessible content does not use color as the sole distinguishing characteristic of a piece. Accessible presentations and content do not use phrases like “as you can see in the red line” or “as you can see in the blue line.” Accessible websites do not use the color red to indicate important notices or errors. The Coblis Color Blindness Simulator can take your graphs, charts, and images and show you what they look like to people with a range of color deficiencies.
Instead of referring to specific colors in your graphs or charts, you should use hashes, dots, dashes, or other line and chart styles that are not color-specific.
Sufficient Visual Contrast
Principle: The EIT must have sufficient visual contrast between the foreground and background.
Individuals with vision deficiencies have a difficult time distinguishing colors and shapes that do not have sufficient contrast between one color or shape and the next. Yellow text on a blue background may be a default template in PowerPoint, but it is highly problematic for individuals with low vision or yellow-blue colorblindness. Blue hyperlinks on a blue background are similarly problematic.
WebAim’s color contrast checker allows you to verify that the colors you choose for text or images in your documents on web pages meet web page contrast requirements. If you are not familiar with hexadecimal notation for colors (common on web pages), you can also use ContrastChecker.com and click on the color palette to bring up an RBG color picker.
Adjustable Font Size
Principle: The font size can be changed without ruining the usability of the document or website.
As we age, it becomes more difficult to discern printed (or screen-based text) at smaller sizes. The internationally recognized web accessibility standards known as the Web Content Accessibility Guidelines (WCAG) require that text can be re-sized without assistive technology up to 200 percent without loss of content or functionality. As such, your documents and web pages need to be able to be fully readable and functional when someone enlarges the text by using the CMD/CTRL + key combination in their web browser.
Clear and Easy Targets
Principle: Buttons and form controls are clearly visible and easily targetable.
Another way of phrasing this principle is that buttons should look like buttons, links should look like links, and all clickable targets in web pages should be large enough to be immediately recognizable as a clickable target. Making clickable targets (i.e., action buttons, form submit buttons, links, etc.) small makes it difficult for most adults to properly click on the target. It makes it virtually impossible for those with motor impairments to do so.
Large-Format Print Documents
If you are required to provide a large print version of a document, the American Council for the Blind provides an excellent set of guidelines for creating large print documents. If you are involved in the publishing of books, the Book Industry Study Group provides a quick start guide to accessible book publishing.