How to Fix Errors of Web Colour Contrast Accessibility Audits

Colour contrast accessibility is one of the most common issues flagged in audits. Even well-designed websites experience low text contrast, poor UI visibility, or background combinations that reduce clarity. These problems directly affect users with low vision, colour blindness, ageing eyes, and even fully sighted users viewing screens in bright light.

In this guide, you’ll understand why colour contrast plays a key role in accessibility, what leads to contrast failures, and how to detect them through reliable testing methods. You’ll also learn practical ways to fix these issues using WCAG-based steps, along with suggested colour combinations, audit checklists, and tools commonly used by accessibility teams worldwide.

What You Will Learn

By the end of this guide, you will know how to:

• Recognise why colour contrast is essential for readability and user access
• Identify the common causes behind colour contrast failures
• Run colour contrast tests using trusted accessibility tools
• Understand contrast ratios and WCAG requirement levels
• Fix low-contrast text, buttons, icons, and UI components
• Apply recommended colour pairings that meet WCAG standards
• Use a checklist to review pages before an accessibility audit
• Choose the right tools for continuous colour contrast monitoring

What Is Colour Contrast Accessibility and Why Does It Matter?

Colour contrast accessibility refers to the minimum visual difference required between foreground and background elements so that text, icons, and interface components remain easy to read. WCAG 2.2 sets the standards for contrast ratio, which must be met for AA or AAA compliance.

Poor colour contrast makes content hard to read, especially for:

• Users with low vision
• People with colour blindness
• Older users
• Users reading on low-quality or small screens
• Mobile users outdoors in sunlight

WCAG 2.2 states:

• Normal text must have at least a 4.5:1 contrast ratio
• Large text (18pt or 14pt bold) must have at least 3:1
• UI components and graphical objects must meet 3:1

When websites fail these requirements, accessibility audits mark them as violations.

Why poor contrast impacts usability

Low contrast text is one of the biggest barriers to reading. It increases cognitive strain, forces users to zoom in, and leads to higher bounce rates. For brands, it reduces conversions, trust, and compliance readiness.

Who is most affected?

Around 300 million people worldwide live with colour blindness. Millions more face age-related visual limitations. Colour contrast errors directly impact their ability to read, navigate, and complete tasks.

What Causes Web Colour Contrast Errors in Accessibility Audits?

Colour contrast issues appear for many reasons, often unintentionally. Audits usually highlight predictable patterns.

Common audit failures related to text and background

Typical issues include:

• Light grey text on white backgrounds
• Pastel colours paired with low contrast typography
• Thin font weights that reduce apparent contrast
• Text placed over images without proper overlays
• Background gradients that make parts of the text unreadable

These failures frequently appear on hero banners, product pages, forms, and marketing blocks.

Issues with icons, buttons, borders, and UI elements

Colour contrast affects more than text. UI components must also meet accessibility guidelines.

Failures often include:

• Low contrast button labels
• Faint border outlines around input fields
• Icons with insufficient foreground contrast
• Unclear focus indicators
• Hover states that lose colour visibility

Buttons and forms often fail because designers focus on style instead of readability.

Brand colours and aesthetic design mistakes

Brand identity palettes with soft tones or minimalistic styles can inadvertently fail WCAG. Designers sometimes prioritise aesthetics over functional contrast, leading to audit errors.

If you want a deeper look at how colour contrast should be tested during accessibility checks, you can also read our detailed guide on how to test colour contrast accessibility using free tools. It explains step-by-step testing methods, contrast ratio checks, and tools that help catch issues early.

How to Identify Colour Contrast Issues on Your Website

You cannot fix colour contrast issues unless you know exactly which elements are failing. Accessibility testing colour tools help identify problem areas across text, icons, buttons, and backgrounds.

How to run a colour contrast checker accessibility test

A contrast checker compares two colours, foreground and background, and calculates the ratio. If the ratio is below WCAG requirements, the result fails.

You can test:

• Page URLs
• HEX / RGB codes
• Screenshots
• Style tiles
• Design system tokens

Top tools for checking colour contrast

You can use the following tools to test text, UI elements, backgrounds, and design components for WCAG-approved contrast ratios:

• Accessibility Assistant Colour Contrast Checker (Shopify + Web Widget)
• WAVE Evaluation Tool
• WebAIM Colour Contrast Checker
• Axe DevTools
• Chrome Lighthouse
• Color Contrast Analyzer (TPGi)
• Stark for Figma
• Accessibility Insights
• Adobe Colour Contrast Checker

These tools scan individual elements or full pages, showing pass/fail results and suggested alternatives.

How to read contrast ratio results

Contrast ratios compare relative luminance.

• 1:1 means no contrast (same colour)
• 21:1 means maximum contrast (black on white)

WCAG thresholds:

• 4.5:1 — Normal text AA
• 3:1 — Large text AA and UI elements
• 7:1 — Normal text AAA

Most auditors expect at least AA-level compliance.

How to Fix Web Colour Contrast Problems Found in Audits

Fixing contrast errors requires adjusting colours, backgrounds, or design components while keeping brand identity intact.

How to choose the best colours for accessibility

Choosing accessible colours doesn’t mean abandoning your brand palette. You can adjust hues, saturation, or luminosity slightly to meet the right ratio.

Consider:

• Darker shades of brand colours for text or buttons
• Lighter or deeper backgrounds for improved separation
• Strong neutrals (black, white, charcoal) for critical UI elements

Adjusting text, background, and UI contrast values

Some simple fixes include:

• Darkening text on light backgrounds
• Increasing the opacity of overlays on hero images
• Lightening backgrounds behind small or thin text
• Adding contrast-friendly borders to form fields
• Reworking button colour pairs

Fixing gradients, overlays, banners, and hero sections

Gradients cause frequent failures because different areas of the gradient can fall below the threshold.

You can fix this by:

• Using a solid overlay with consistent opacity
• Adding a colour block behind text
• Adjusting gradient values to meet the minimum contrast
• Increasing text weight or size

Creating accessible colour combinations

Below is a sample table you can include:

Use combinations that maintain readability across devices and modes.

How to maintain visual identity while fixing contrast

Most brands can remain consistent with minor adjustments, such as:

• Increasing darkness by 5–15%
• Using bolder weights instead of lighter ones
• Adding contrast-safe accent colours
• Adjusting saturation instead of changing the base colour

These small tweaks preserve brand perception without sacrificing accessibility.

How to Pick the Best Colour Contrast for Website Accessibility

Good contrast design involves more than passing audits. It must support readability across real-world scenarios.

Practical contrast ratio rules for designers

For effortless compliance:

• Use at least 4.5:1 for normal text
• Use at least 3:1 for large text
• Avoid thin typefaces
• Avoid light backgrounds without strong contrast
• Test every text style, not just body copy

How to create a colour system for long-term WCAG compliance

A sustainable colour system includes:

• Primary accessible colours
• Secondary accents with safe ratios
• Contrast-approved text tones
• Safe button and link colour variations
• High-contrast mode equivalents
• Light and dark theme compatibility

Document these choices in your design system.

Using dark mode and high-contrast mode correctly

Dark mode improves comfort for many users, but can create new contrast issues.

Follow these tips:

• Avoid pure black on pure white
• Ensure text brightness meets contrast ratios
• Don’t rely exclusively on colour for meaning
• Test dark mode separately

How to Prevent Colour Contrast Errors in Future Audits

Prevention is easier than fixing errors repeatedly.

Adding contrast checks in your design workflow

Include contrast testing during:

• Wireframing
• Visual design
• UI prototyping
• Component creation
• Development QA
• Pre-launch validation

Building an internal colour accessibility guideline

Create a small internal checklist:

• Approved colour combinations
• Accessible text/background pairs
• Colour tokens with ratios
• Visual examples of fails and passes
• Rules for images, gradients, and overlays

Why is regular accessibility testing colour important

Colour visibility varies on:

• New monitors
• Different phone models
• Outdoor light
• Night mode

Testing regularly prevents issues before audits detect them.

Final Checklist for Colour Contrast Accessibility Compliance

Include this as a visible bullet list:

• All text meets the minimum ratio
• Logos and brand marks are visible
• Buttons and links are readable
• Form input borders clear
• Focus and hover states are visible
• Dark mode tested separately
• Gradients and images reviewed
• No text placed on busy backgrounds

This checklist makes audits smoother and reduces rework.

FAQs About Colour Contrast Accessibility

1. What is the ideal colour contrast ratio for WCAG?

WCAG recommends 4.5:1 for normal text and 3:1 for larger text. For the AAA level, the ratio rises to 7:1.

2. How do I check colour contrast for my website?

Use tools like WAVE, WebAIM, Lighthouse, or Axe. They evaluate colours, UI elements, and text combinations.

3. What colour contrast issues fail most accessibility audits?

The most common failures include low contrast text, faint button labels, unclear form fields, text on images, and weak icon contrast.

4. Can I fix contrast issues without changing my brand colours?

Yes. Often, you can adjust brightness, shade, or saturation instead of replacing your palette.

5. Do gradients and images affect contrast ratings?

Yes. Since contrast varies across gradients or images, small sections may fail even if other sections pass.

Conclusion

Colour contrast accessibility is essential for making websites readable, usable, and WCAG-compliant. A strong contrast system supports all users, reduces audit failures, and improves engagement. With proper testing, contrast checkers, colour adjustments, and consistent guidelines, you can maintain an accessible visual experience across every device and platform.