Designing for Usability with Color Blind Users in Mind

Color blindness, also known as color vision deficiency (CVD), is one of the most common visual impairments, affecting the ability to distinguish certain colors. It is estimated that around 8% of men and 0.5% of women worldwide are affected. In the context of digital design, neglecting the needs of people with CVD can exclude users and result in the loss of potential customers.

Color blindness can be classified into several types, the most common being:

• Protanopia – the inability to perceive red hues.
• Deuteranopia – the inability to perceive green hues.
• Tritanopia – the inability to perceive blue and yellow hues.
• Achromatopsia – total color blindness; vision is limited to shades of gray.

Each type affects how users perceive digital content, which can significantly impact their ability to use websites or applications.

Insufficient Color Contrast

Poor contrast between text and background can make content unreadable for users with CVD. According to WCAG 2.2 guidelines, the minimum contrast ratio should be 4.5:1 for regular text and 3:1 for large text.

Reliance on Color Alone

Using color as the sole means of conveying information—such as in forms or charts—can cause confusion. Users with CVD may not perceive important elements, like error messages or distinctions in data visualizations.

Navigation and Interaction Issues

Interactive elements like buttons or links that rely solely on color changes for state indication may be hard to detect. A lack of alternative cues—such as shape changes or added text—can hinder usability and navigation.

Avoid Relying on Color Alone

Instead of using color as the only information channel, include additional indicators such as text labels, icons, or patterns. For example, a red error message can be supplemented with a warning icon and a descriptive message.

Ensure Sufficient Contrast

When choosing colors, make sure text remains legible against the background. Tools like the WebAIM Contrast Checker can help ensure compliance with accessibility standards.

Use Textures and Patterns

When color is used to differentiate elements — such as in bar charts — incorporating patterns or textures can help users distinguish them more easily.

Add Clear Labels and Descriptions

Every interactive element should have a descriptive text label. Form fields should include clear instructions, and buttons should have meaningful labels (e.g., “Submit Form” instead of “Submit”).

Designing with color vision–deficient users in mind makes websites and applications more accessible not only to them but also to older adults and people with other visual impairments. Applying accessibility principles, such as proper contrast and clear labeling, improves the overall usability of digital interfaces. Users are able to find information more easily and complete tasks more efficiently.

Furthermore, many countries are introducing legislation mandating digital accessibility. For example, the European Accessibility Act, effective from June, requires most digital sectors to comply with WCAG 2.1 standards for websites and mobile applications.

But that’s not all—organizations that invest in accessibility benefit from enhanced brand reputation and increased customer loyalty. Accessibility can also improve conversion rates and revenue, as users with color vision deficiencies represent a significant portion of the population.

• Color Oracle – simulates various types of color blindness
• Sim Daltonism – macOS app for simulating color vision deficiencies
• WebAIM Contrast Checker – checks color contrast against WCAG guidelines
• ColorBrewer – generates color palettes with accessibility considerations
• Cmaputil – Python module for generating CVD-optimized colormaps

Designing for users with color vision deficiencies is not only an ethical responsibility. It’s also a smart business decision. Following accessibility best practices such as ensuring adequate contrast, avoiding color-only indicators, and incorporating patterns or textures results in more usable and inclusive digital products. Investing in accessibility is a step toward a more effective and equitable digital experience for all.