Micro-Contrast Highlighter
Accessibility contrast checker for designers
Spot Low-Contrast Areas Before Your Users Do
Micro-Contrast Highlighter is a free online tool that helps designers identify and fix low-contrast elements in images and designs that are just below accessibility thresholds.
What this tool DOES: Highlights areas where contrast ratios are between 3.5:1 and 4.4:1 (just below WCAG AA requirements) to help you identify problem areas before finalizing designs.
What this tool does NOT: It does not fix contrast issues automatically, nor does it guarantee full WCAG compliance. It's a helper tool for designers.
Left: Original design. Right: After analysis with low-contrast areas highlighted in pink.
Micro-Contrast Highlighter Tool
Upload your image or design file to detect areas with contrast ratios just below accessibility standards (WCAG AA).
Upload Your Design
Drag & drop or click to browse
Supported: JPG, PNG, GIF, SVG, WEBP (Max: 5MB)
Selected File: No file selected
Size: -
Dimensions: -
Tip: For best results, use screenshots of your web designs, app interfaces, or graphic designs. The tool works best with clear text-over-background areas.
Analysis Results
No image analyzed yet
Upload an image and click "Highlight Low-Contrast Areas" to see results
How It Works
The Micro-Contrast Highlighter analyzes your images using a specialized algorithm to detect subtle contrast issues.
Upload Your Design
Upload any image file containing your design, interface, or graphic. The tool accepts JPG, PNG, GIF, SVG, and WEBP formats.
Algorithm Analysis
Our algorithm scans the image pixel by pixel, identifying areas where foreground and background colors have contrast ratios between 3.5:1 and 4.4:1.
Highlight Problem Areas
Areas with contrast just below the WCAG AA threshold of 4.5:1 are highlighted with a semi-transparent overlay, making them easy to identify.
Review & Fix
Download the annotated image and use it as a guide to adjust contrast in your design tools, improving accessibility.
About the Algorithm
The tool uses a modified version of the WCAG 2.1 contrast ratio formula to calculate luminance differences between adjacent pixels. It specifically flags areas where the contrast ratio falls in the "micro-contrast" range—just below the 4.5:1 threshold required for normal text by WCAG AA standards.
This approach helps you catch subtle contrast issues that might pass a quick visual check but fail accessibility tests, particularly for users with low vision or color vision deficiencies.
Why Use Micro-Contrast Highlighter
This tool helps designers create more accessible and user-friendly designs with minimal effort.
Accessibility Compliance
Identify and fix contrast issues before they become accessibility problems, helping you meet WCAG 2.1 AA standards.
Design Verification
Double-check your designs for subtle contrast issues that are hard to spot with the naked eye but affect readability.
Improved Readability
Ensure all users can comfortably read your content, regardless of visual abilities or screen conditions.
Fast & Free
Get instant results without subscriptions or complex setup. The tool runs entirely in your browser.
Beginner-Friendly
No accessibility expertise required. The tool highlights problem areas visually, making fixes straightforward.
Privacy Focused
Your images are processed locally in your browser—never uploaded to our servers. Your designs stay private.
How to Use Micro-Contrast Highlighter
A comprehensive guide for designers of all skill levels to identify and fix low-contrast issues.
Introduction to Contrast Accessibility
Contrast accessibility refers to the difference in luminance or color that makes text and interactive elements distinguishable from their background. The Web Content Accessibility Guidelines (WCAG) 2.1 specify minimum contrast ratios for text and images of text to ensure readability for people with visual impairments, including color blindness and low vision.
The WCAG 2.1 AA standard requires a contrast ratio of at least 4.5:1 for normal text and 3:1 for large text (18pt or 14pt bold). However, many designs contain "micro-contrast" issues—areas where the contrast ratio is close to but just below these thresholds. These subtle issues often go unnoticed during design reviews but can create significant accessibility barriers.
Why Micro-Contrast Matters: Designs with contrast ratios between 3.5:1 and 4.4:1 might look acceptable to designers with typical vision but can be difficult or impossible to read for users with visual impairments. Our tool specifically targets this "danger zone" to help you catch issues before they affect users.
Step-by-Step Guide to Using the Tool
1. Preparing Your Design Files
Before using the Micro-Contrast Highlighter, prepare your design files appropriately:
- Export at appropriate resolution: For web designs, export at 1x or 2x resolution. For print designs, use a resolution that shows detail without being excessively large.
- Include text layers: Make sure all text elements are visible and not flattened into the background unless that's how they'll appear in the final product.
- Consider different states: For interactive elements, consider checking hover states, focused states, and disabled states separately.
- Remove sensitive data: Since you'll be uploading files, ensure they don't contain sensitive or proprietary information if you're concerned about privacy.
2. Uploading Your Design
The upload process is straightforward:
- Click the upload area or drag and drop your file into the designated zone.
- Supported formats include JPG, PNG, GIF, SVG, and WEBP. Maximum file size is 5MB.
- Once uploaded, you'll see file details including name, size, and dimensions.
- If you select the wrong file, use the reset button or simply upload a different file.
Note: The tool processes images locally in your browser using JavaScript. This means your images never leave your computer, ensuring complete privacy. However, it also means very large images (over 5MB) may cause performance issues on older devices.
3. Analyzing the Design
After uploading, click the "Highlight Low-Contrast Areas" button. The tool will:
- Process the image pixel by pixel to identify contrast ratios
- Flag areas where contrast falls between 3.5:1 and 4.4:1
- Generate a visual overlay highlighting these areas
- Provide a count of detected issues
Processing time depends on image size and complexity but typically takes 2-10 seconds for most design files.
4. Interpreting the Results
The results show your original design with a semi-transparent pink overlay highlighting low-contrast areas. Here's how to interpret what you see:
- Solid pink areas: These indicate regions with consistent low-contrast issues, often where text meets background.
- Partial overlays: Some areas may have partial highlighting, indicating that only parts of that region have contrast issues.
- No overlay: Areas without highlighting have sufficient contrast (above 4.5:1) or contrast that's too low (below 3.5:1) to be in the "micro-contrast" range.
Interpreting Edge Cases: Sometimes the tool may highlight edges or gradients that technically have contrast in the target range but aren't text elements. Use your judgment—if it's not text or an important interface element, it may not need adjustment. The tool is designed to catch potential issues, not to make definitive accessibility judgments.
Practical Examples for Different Design Types
Web Design Examples
For web designs, pay special attention to:
- Body text: The most common issue is light gray text on white or off-white backgrounds.
- Placeholder text: Often has lower contrast intentionally, but should still be perceivable.
- Button text: Text on colored buttons frequently falls into the micro-contrast range.
- Form labels: Light labels on white backgrounds are a common accessibility failure.
- Navigation items: Both active and inactive states should have sufficient contrast.
Example Fix: If your analysis shows light gray (#999999) text on a white (#FFFFFF) background has a contrast ratio of 3.9:1, you would need to darken the text to at least #767676 to achieve 4.5:1 contrast.
// Light gray text: #999999 on white: #FFFFFF
// Contrast ratio: 3.9:1 (below WCAG AA)
// Solution: Darken text to #767676
// New contrast ratio: 4.5:1 (meets WCAG AA)
Mobile App Interface Examples
Mobile interfaces have unique challenges:
- Small text sizes: On mobile, text is often smaller, making contrast even more critical.
- Touch targets: Button labels and icons need clear contrast to be identifiable.
- Status indicators: Success, warning, and error messages should have both color and contrast differentiation.
- Dark mode: Check both light and dark themes separately as contrast issues differ.
Graphic Design & Marketing Materials
For posters, flyers, social media graphics, and other marketing materials:
- Headlines: Large text still needs sufficient contrast, especially if it's the primary message.
- Text over images: A common issue where text is placed over busy or light areas of photos.
- Data visualization: Charts and graphs need sufficient contrast between data points and backgrounds.
- Brand colors: Sometimes brand color combinations don't meet contrast requirements and need adjustment for accessibility.
Fixing Contrast Issues
Adjusting Colors in Design Tools
Once you've identified problem areas, here's how to fix them in popular design tools:
In Figma:
- Select the element with contrast issues
- Open the color picker
- Use the contrast checker in the color picker (available in Figma's built-in tools)
- Adjust lightness/darkness until you achieve at least 4.5:1 contrast
- Consider creating accessible color variants in your design system
In Adobe Photoshop/Illustrator:
- Use the "Proof Colors" feature to simulate how colors appear to users with color vision deficiencies
- Adjust colors using the Color Picker or Adjustments panel
- For text, ensure you're using actual text layers rather than rasterized text for easier adjustment
In Sketch:
- Use the "Contrast" plugin (available in Sketch plugin ecosystem)
- Alternatively, manually adjust colors using the color picker
- Create shared styles for text to ensure consistency across your design
General Color Adjustment Strategies
- Increase difference in lightness: The most effective way to improve contrast is to increase the lightness difference between foreground and background.
- Use color with caution: Remember that color difference alone doesn't guarantee sufficient contrast—lightness difference is key.
- Add borders or shadows: For text on complex backgrounds, consider adding a subtle border or shadow to increase contrast.
- Consider opacity: Sometimes reducing background opacity (or increasing text opacity) can improve contrast.
Common Mistakes to Avoid
1. Over-Reliance on Color Differences
Many designers assume that if two colors are different (e.g., red and green), they have sufficient contrast. However, contrast is primarily about luminance (lightness), not hue. Red and green can have identical luminance values, making them indistinguishable to some users with color blindness.
2. Assuming Large Text Needs Less Contrast
While WCAG allows a lower contrast ratio (3:1) for large text (18pt or 14pt bold), this doesn't mean large text can have poor contrast. Many users with visual impairments still struggle with low-contrast large text, especially in challenging lighting conditions.
3. Ignoring Different States
Interactive elements like buttons, links, and form fields have multiple states (normal, hover, focus, active, disabled). Each state must maintain sufficient contrast. A common mistake is creating beautiful hover states that fail contrast requirements.
4. Forgetting About Context
Contrast requirements can vary based on context. Decorative text that's not essential for understanding content may not need to meet strict contrast requirements. However, any text that conveys information or is interactive should meet WCAG standards.
Advanced Tips for Professional Designers
1. Build Accessibility into Your Design System
Instead of fixing contrast issues one element at a time, build accessibility into your design system:
- Define accessible color pairs in your color palette
- Create text styles with predefined contrast-safe combinations
- Document contrast ratios alongside color values
- Include accessibility requirements in component documentation
2. Test with Real Users
While tools like Micro-Contrast Highlighter are valuable, nothing replaces testing with real users, particularly those with visual impairments. Consider:
- Conducting usability tests with participants who have visual impairments
- Using simulation tools to experience your designs with different visual conditions
- Testing in various lighting conditions (bright sunlight, dim rooms)
3. Consider the Entire Experience
Accessibility is more than just contrast. Consider these related factors:
- Focus indicators: Ensure interactive elements have visible focus states with sufficient contrast
- Text spacing: Line height, letter spacing, and paragraph spacing affect readability
- Responsive behavior: Ensure contrast is maintained across all screen sizes and orientations
- Motion: Consider users with vestibular disorders who may be affected by certain animations
Conclusion
The Micro-Contrast Highlighter is designed to be a practical, easy-to-use tool that fits seamlessly into your design workflow. By catching subtle contrast issues early in the design process, you can create more accessible, user-friendly products without significant rework.
Remember that accessibility is an ongoing process, not a one-time checklist. Regular use of this tool, combined with other accessibility practices, will help you develop an instinct for creating accessible designs from the start.
Final Tip: Make the Micro-Contrast Highlighter part of your design review process. Before sending designs to clients or developers, run them through the tool to catch any last-minute contrast issues. This simple step can save significant time and resources compared to fixing accessibility issues after development has begun.
Frequently Asked Questions
Find answers to common questions about the Micro-Contrast Highlighter tool.
The tool supports JPG, PNG, GIF, SVG, and WEBP formats. Maximum file size is 5MB. For best results with text analysis, use PNG or WEBP formats as they maintain better image quality without compression artifacts that can affect contrast detection.
The tool uses the same luminance calculation formula specified in WCAG 2.1 guidelines, making it highly accurate for contrast ratio detection. However, it analyzes static images, so it cannot account for dynamic content, hover states, or CSS effects that might affect contrast in the final implementation. It's designed as a design helper, not a replacement for comprehensive accessibility testing.
No. All image processing happens locally in your browser using JavaScript. Your designs never leave your computer, ensuring complete privacy and security for proprietary or confidential designs. This also means the tool works without an internet connection after the initial page load.
The tool highlights areas where contrast ratios are between 3.5:1 and 4.4:1. This "micro-contrast" range is just below the WCAG AA requirement of 4.5:1 for normal text. We focus on this range because these subtle issues are often missed in design reviews but still create accessibility barriers. The tool does not flag areas with contrast below 3.5:1 (which are usually obvious) or above 4.5:1 (which meet requirements).
Yes, the tool can analyze designs with gradients and image backgrounds. However, it analyzes contrast pixel by pixel, so areas where text crosses multiple background colors or gradients may show partial highlighting. For complex backgrounds, the tool helps identify problematic sections, but you may need to make manual adjustments like adding background overlays or adjusting text positioning to ensure consistent contrast across all areas.
No. The Micro-Contrast Highlighter is specifically designed to catch subtle contrast issues during the design phase. It does not check for other accessibility requirements like keyboard navigation, screen reader compatibility, focus management, semantic HTML, or ARIA attributes. We recommend using this tool alongside other accessibility testing methods, including automated checkers, manual testing, and user testing with people with disabilities.
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