Color Blindness Simulator

Simulates different types of color blindness using SVG filters.

Color Blindness Simulator is a privacy-focused Chrome extension that helps users preview how webpages may appear to people with different types of color blindness. It is designed for web developers, UI designers, accessibility auditors, product teams, students, educators, and curious sighted users who want to better understand how color choices affect readability, usability, and visual communication. By applying full-page simulation filters directly in the browser, the extension makes it easier to test whether a design still works when colors are perceived differently. Color is a major part of web design. It is used to communicate status, hierarchy, warnings, success messages, links, charts, buttons, labels, navigation states, form errors, and brand identity. However, if a page relies too heavily on color alone, some users may miss important information. A red error message, green success indicator, blue link, orange warning, or color-coded chart may not be equally clear for everyone. Color Blindness Simulator helps reveal these issues by showing how the same page may look under different color vision conditions. The extension supports several simulation modes, including **deuteranopia**, **protanopia**, **tritanopia**, and **achromatopsia**. Deuteranopia is commonly associated with difficulty distinguishing certain green tones. Protanopia affects perception of certain red tones. Tritanopia affects blue-yellow color perception. Achromatopsia simulates a grayscale-like view where color information is largely removed. By switching between these modes, users can see whether the page still communicates clearly without relying only on normal color perception. Color Blindness Simulator works entirely inside Chrome and does not use any external API. No data is ever transmitted to third-party servers. The simulation is applied locally on your device using SVG color matrix filters that affect the full page visually in the browser. The extension does not upload webpage content, screenshots, URLs, browsing history, design data, user settings, personal information, or usage activity. Everything happens locally inside Chrome, giving users a private and secure way to test visual accessibility. Privacy is especially important for a development and accessibility testing tool. Designers and developers may test public websites, private prototypes, staging environments, internal dashboards, client projects, product interfaces, admin pages, and unreleased designs. Color Blindness Simulator is designed so that this work remains local. It does not send page data to cloud accessibility services, does not rely on remote image processing, does not transmit screenshots, and does not require an account. Your testing activity stays on your device. The extension uses SVG color matrix filters to simulate color perception changes across the full webpage. This approach allows the entire visible page to be transformed at once, including text, images, buttons, icons, backgrounds, charts, cards, forms, and layout elements. Because the filter is applied locally as a visual layer, it does not permanently change the website’s code, design files, or assets. It simply changes how the page appears to you while the simulator is active. A quick-switch dropdown makes it easy to cycle between simulation modes. Instead of opening settings repeatedly or reloading the page for each condition, users can choose a mode from the dropdown and immediately compare how the interface changes. This is useful during design reviews, QA checks, accessibility audits, and live debugging sessions. Fast switching encourages users to test more than one condition instead of checking only a single view. For developers, Color Blindness Simulator can be a practical tool during implementation. It can help identify interface elements that depend too heavily on color, such as buttons that only change color on hover, status badges that lack text labels, charts with similar color series, form errors indicated only in red, or disabled states that become hard to distinguish. When these issues are spotted early, developers can improve the interface with labels, icons, patterns, contrast adjustments, underlines, borders, or clearer text. For designers, the extension helps evaluate color systems in context. A palette may look attractive in a design file, but real usability depends on how colors work together across actual components. Color Blindness Simulator can show whether primary actions remain obvious, whether warnings and success states are distinguishable, whether charts are readable, and whether visual hierarchy remains clear. This can lead to more inclusive design decisions without requiring a complicated workflow. Accessibility auditors and QA testers can use the extension as part of manual testing. It is not a replacement for screen reader testing, keyboard testing, contrast measurement, semantic review, or full accessibility audits, but it is a useful visual inspection tool. It helps reviewers quickly understand whether color-dependent information may become unclear under different simulated views. The extension can support conversations with design and engineering teams by making potential problems visible. Educators and students can also use Color Blindness Simulator for learning. It can help explain why accessible design matters and why color should not be the only way to communicate information. Students studying web design, human-computer interaction, digital media, or accessibility can use the tool to compare real websites and understand how inclusive design principles apply in practice. Curious sighted users may also find the extension valuable. It offers a simple way to understand how webpages can look different to people with color vision differences. This can build empathy and awareness, especially for users who create content, share graphics, build websites, or make presentations. Because the extension does not use external APIs or third-party servers, it remains lightweight and responsive. There is no upload process, no cloud rendering delay, no login requirement, and no remote processing. The visual simulation is applied directly in Chrome, so users can test pages quickly and privately. Color Blindness Simulator is ideal for anyone who wants a private, local, and easy-to-use way to preview color accessibility issues. No external API is used. No data is ever transmitted to third-party servers. Your webpage content, screenshots, URLs, browsing activity, settings, and testing results remain on your own device. With its deuteranopia, protanopia, tritanopia, and achromatopsia modes, SVG color matrix filters, full-page visual simulation, quick-switch dropdown, local processing, and privacy-first design, Color Blindness Simulator is a practical Chrome extension for building more accessible and inclusive web experiences.