Why is Colour Contrast Important for Accessibility?

Colour is one of the most powerful elements of web design, playing a huge role in creating that all-important first impression. Designers spend a lot of time choosing the right colours to make websites look appealing and to express brand identity. But what many don’t realise is that your site may not look the same to everyone. While you may think it looks amazing, it could be limiting some users from fully engaging with your content.

Without sufficient colour contrast, key elements on your site can become difficult to see, limiting accessibility and making your website less inclusive. Ensuring that your design works for everyone, regardless of their visual abilities, is essential for creating a user-friendly experience that benefits all visitors.

What Is Colour Contrast?

Colour contrast refers to the difference in luminance between two colours, usually between text and its background. Luminance measures how much light a colour reflects or emits, determining how bright or dark it appears to the human eye.

One way to measure this contrast is through a contrast ratio, which compares the relative brightness of two colours. A higher contrast ratio means the colours stand out more from each other, making the content easier to read. For example, black text on a white background has the highest contrast ratio possible at 21:1, meaning the two colours are very distinct from each other.

On the other hand, if the colours are too similar, such as white text on a pale yellow background, the contrast ratio could drop as low as 1:1, making it nearly impossible for many users to read the text clearly. That’s why maintaining sufficient contrast between colours is essential for making content readable to everyone, not just those with visual impairments.

What Level of Colour Contrast Do I Need to Meet Accessibility Standards?

The Web Content Accessibility Guidelines (WCAG) 2.2 set clear standards for colour contrast to ensure websites are inclusive and accessible to all users. According to these guidelines, a minimum contrast ratio of 4.5:1 is required for normal text. This ratio helps make sure that text is easily readable against its background, particularly for users with visual impairments.

However, there are three key exceptions to this rule:

• Large Text: Text that is 18pt and larger (or 14pt if bold) has a lower contrast requirement, with a minimum ratio of 3:1, as larger text is naturally easier to read.
• Incidental Text: Text that is purely decorative, part of inactive user interface elements, not visible to anyone or embedded within complex images doesn’t need to meet contrast requirements.
• Logotypes: Text within logos or brand names is also exempt from contrast ratio guidelines, as these elements often serve a different purpose.

Your eyes alone can’t determine whether your colour choices meet accessibility standards. Thankfully, there are several online tools available to help you check the contrast ratios of your website’s elements. A reliable option is the WebAIM Contrast Checker, which makes it easy to ensure that your colour choices are effective and compliant.

Best Practices for Designing with Colour Contrast

Accessible design often gets misunderstood as being boring or difficult to implement, but that couldn’t be further from the truth. By paying attention to how colours work together, you can create a site that looks great while being accessible to all. Here’s how you can achieve that balance:

Avoid Using Colour Alone to Convey Information

Relying solely on colour to communicate important information can create barriers for users with visual impairments. If, for example, red text is used to signal an error without any other visual cues, it might go unnoticed by those who can’t distinguish colours well. To avoid this, always pair colour with other indicators, such as icons, bold text or underlines. This way, you’re making it clear to all users, regardless of their ability to perceive colour.

Test in Different Lighting Conditions

Colours that look good in one environment might not perform well in another. Light text on a light background might seem perfectly clear on your bright office screen but can become unreadable in dim light or direct sunlight. Testing your website in various lighting conditions and on different devices helps ensure that your content remains legible no matter where or how it’s viewed.

Ensure Contrast for Interactive Elements

Interactive elements like buttons, links and form fields are crucial for navigation, yet they’re often overlooked when it comes to contrast. If these elements don’t stand out enough, users may struggle to identify or interact with them. To make navigation effortless, ensure that all interactive elements have strong contrast with their background, making them easy to spot and engage with.

Check for Consistency Across Your Design

Inconsistent contrast throughout your website can lead to a confusing experience for users. While one part of your site might meet accessibility standards, another section might fall short, causing frustration and reducing overall usability. Maintaining consistent colour contrast across all design elements—whether it’s for text, headers, icons or buttons—creates a smooth, cohesive experience for visitors as they move through your site.

Make Accessibility a Priority in Your Website

Colour contrast is one of the most important tools designers use to make websites more accessible, but it’s only part of the solution. While ensuring strong contrast is essential for readability and usability, achieving a fully accessible website requires a more comprehensive approach. Accessibility means designing a site that all users, regardless of physical or cognitive ability, can easily navigate, understand and interact with.

This concept is at the heart of every website we design and build at Priority Pixels, ensuring accessibility is never an afterthought. If you’re unsure whether your existing site meets these standards, it may be time for an accessibility audit. Our team can identify any areas that need improvement and implement the necessary changes to ensure your website is truly inclusive for all visitors.