---
title: "Color Blindness Simulator for Images | CanDoYa"
description: "Color blindness simulator for images with protanopia, deuteranopia, tritanopia and achromatopsia views. Private, free and browser-based."
url: https://candoya.com/tools/color-blindness-simulator/
locale: en
type: browser-tool
---

# Color Blindness Simulator

Category: Color & Design

## What is a color blindness simulator?

A color blindness simulator changes an image to approximate how colors may appear with protanopia, deuteranopia, tritanopia or achromatopsia. Upload a design or photo, choose a vision type and compare both views side by side. Processing stays in your browser, so the image is not uploaded.

Use the strength control to inspect a milder or full simulation, then copy or download the transformed image for a design review. **Your image stays on your device**; the browser reads its pixels, applies the selected transform and renders the result locally.

A simulation can reveal color pairs that collapse into similar tones, but it does not certify accessibility. Pair this check with contrast measurements, text labels, icons, patterns and user testing.

## How to use it

1. **Choose an image** - Upload a PNG, JPG, WebP or AVIF file, drag it into the drop zone, or load the built-in color example.
2. **Select a vision type** - Compare protanopia, deuteranopia, tritanopia or achromatopsia, then adjust the simulation strength if needed.
3. **Review both views** - Inspect the original and simulated canvases side by side. Look for controls, labels or chart series that become hard to tell apart.
4. **Save the result** - Copy the simulated image to the clipboard or download it as a PNG for review notes and issue reports.

## Who it's for

- **Product designers** checking whether status colors, charts and controls remain distinguishable without hue alone.
- **Front-end developers** reviewing screenshots before adding labels, patterns or stronger contrast.
- **Data visualization teams** finding series colors that merge under red-green or blue-yellow deficiencies.
- **Teachers and creators** comparing how photos, diagrams and learning materials may be perceived.

## Expert note

The simulation applies the full-severity Machado, Oliveira and Fernandes color-vision-deficiency matrices in linear RGB, then blends toward the original for lower strengths. It is useful for spotting risky color dependence, but individual perception varies and the result is not a diagnosis.

## Frequently asked questions

### Is my image uploaded?

No. Your browser decodes the image, transforms its pixels and creates the preview locally. The tool does not send the file to a server. If the image is sensitive, you can use the simulator without creating an account or saving it online.

### Is the color blindness simulator free?

Yes. You can upload images, switch between the available simulation modes, change the strength and download results for free. There is no sign-up and no per-day usage limit.

### What image limits apply?

The simulator accepts PNG, JPG, WebP and AVIF files up to 20 MB and 32 million pixels. Very large images are scaled for the on-page preview, while the downloaded PNG is rendered from the original image dimensions.

### Which types of color blindness can I simulate?

The tool includes protanopia, deuteranopia and tritanopia, plus an achromatopsia view. Protanopia and deuteranopia affect red-green discrimination, while tritanopia affects blue-yellow discrimination. Achromatopsia is shown as a no-color approximation.

### Is this simulation medically accurate?

No simulator can reproduce one person's exact perception. This tool uses an established mathematical model to support design review, not medical screening or diagnosis. Perception varies with the type and severity of color vision deficiency, the display and viewing conditions.

### Does a good simulated result mean my design is accessible?

Not by itself. A design should also meet relevant contrast requirements and avoid using color as the only cue. Add text, icons, shapes or patterns where meaning could disappear, and include disabled, hover, focus and error states in your review.

### Can I use the simulator offline?

After the page has loaded, the image processing itself does not need an upload or remote conversion service. Browser caching determines whether the whole page can reopen without a network connection.

## Related tools

- [WCAG Contrast Checker](https://candoya.com/tools/wcag-contrast-checker/)
- [Accessible Palette Generator](https://candoya.com/tools/accessible-palette-generator/)
- [Color Contrast Checker](https://candoya.com/tools/color-contrast-checker/)
- [Color Palette Generator](https://candoya.com/tools/color-palette-generator/)
- [Image Color Picker](https://candoya.com/tools/image-color-picker/)

---

*Markdown edition of <https://candoya.com/tools/color-blindness-simulator/>, published for AI agents and other automated readers. Index of key pages: <https://candoya.com/llms.txt>.*