Few objects are remarkable when considered on their own: It’s usually that particular object’s qualities, relative to the qualities of the objects around it, that lend it significance. Hence, the importance of design.
One of the ways web designers help internet users focus attention on the significant portions of a website is through the use of color. The artful use of color guides the eyes, which is vital to conveying a website’s underlying value proposition. The proper use of contrasting colors also enhances accessibility for internet users affected by visual disabilities.
Common Conditions That Affect Vision
Many visually disabled internet users see well enough so that they routinely access the World Wide Web without the use of assistive technologies. These users may be affected by a number of different conditions, including:
• Tunnel vision: Tunnel vision is a reduction in peripheral vision that’s often associated with common disorders like diabetic retinopathy, cataracts, glaucoma and age-related macular degeneration.
• Blurred vision: Blurred vision is a diminishment of visual acuity that can also be associated with the conditions listed above.
• Color blindness: Color blindness is the inability to distinguish between one or more primary colors. It’s estimated that approximately 4.5 percent of the world’s population is affected by some form of color blindness.
Best Practices
“Website users who have low vision, low contrast vision, or color vision deficiency will require color choices that adhere to the Web Content Accessibility Guidelines (WCAG) standards in order to read content,” note the experts at the Bureau of Internet Accessibility. Here’s a look at some of those WCAG guidelines:
• Use the proper contrast ratio: The WCAG recommends setting the contrast between text and background at 3:1 for large text and 4.5:1 for small text. This will help ensure that people whose visual disability affects their contrast sensitivity will still be able to distinguish text from background. These minimum contrast requirements do not apply to logos or other branding elements.
• Don’t use color to communicate significance: A common blunder that’s often made by inexperienced web designers, particularly those who are unaware of WCAG guidelines, involves the use of a red font to make key points stand out from other text. Any user who has red-green colorblindness will miss those points.
• Don’t use color to distinguish chart elements: Colorblind users may also find it difficult to distinguish between points on a chart or a graph if those points are distinguished by color alone. Experts recommend the use of texture to help users distinguish between these types of elements.
• Provide text alternatives: Many users with visual disabilities access websites with the screen reader or another assistive technology. Always make sure that every image on a website includes an ALT tag that accurately describes what the image portrays.
