Process up to 200 images per job — pick your settings once, run them all.
Roughly 8% of men and 0.5% of women have some form of colour vision deficiency. This tool simulates how your image looks to someone with each common type — protanopia (red-blind), deuteranopia (green-blind), tritanopia (blue-blind), and full achromatopsia (greyscale). Use it on charts, UI screenshots, or photos to catch invisible accessibility failures before users do.
What each type means
- Protanopia (1% of men): can't see red. Red appears as dark grey-yellow.
- Deuteranopia (1% of men): can't see green. Most common form. Reds and greens look similar.
- Tritanopia (very rare): can't see blue. Blues and yellows look similar.
- Achromatopsia (extremely rare): no colour vision at all — pure greyscale.
- Anomalous trichromacy (5% of men): reduced sensitivity rather than absence. We simulate the moderate case.
What to look for
- Chart legends that rely on colour alone. Red and green lines indistinguishable to deuteranopes.
- Form errors marked only with red. Pair with an icon or text label.
- Status indicators. Traffic-light red/yellow/green schemes are the worst case.
- Pie charts and stacked bars. Adjacent slices in similar hues lose their boundaries.
Pair with the contrast checker
Colour-blindness is one accessibility axis; contrast is the other. Run Contrast Checker on the same screenshots to verify WCAG AA / AAA compliance for foreground / background pairs.
Use case: data viz
Default chart palettes (matplotlib's tab10, Excel's defaults) include problematic pairs. Run your dashboard through this and see which series collide. Recommended replacements: viridis, cividis, ColorBrewer's accessible diverging palettes.
Frequently asked questions
How accurate is the simulation?
It's a perceptual approximation based on published research (Brettel et al.). Real colour-vision-deficient users may see slight variations, but the approximation is good enough to catch design failures.
What input formats are supported?
JPG, PNG, WebP, HEIC. Up to 25 MB. Works on photos, screenshots, design files.
Can I download all four simulations at once?
Yes — export as a 2×2 grid PNG showing all four side-by-side, plus the original. Useful for sharing in design reviews.
Does it work on video?
No, image only. For video, simulate one representative frame.
Why do my reds look brown?
That's deuteranopia — the colour cone for green is reduced, so reds shift towards browns and dark yellows.
What about animated GIFs?
We process the first frame. Run static frames separately if you need the full sequence.
Is it for diagnosing colour blindness?
No — this is a design tool. Diagnostic Ishihara plates require a clinical setting.
What's the WCAG guidance on colour?
WCAG 1.4.1 says 'colour is not used as the only visual means of conveying information'. Always pair colour with shape, label, or pattern.
About Color Blindness Simulator
Color Blindness Simulator is a free online tool from Wallpapers.com that runs entirely in your browser — no install, no watermark, no email sign-up for the first try.
Preview how your design looks to people with color-vision deficiencies.
How to use Color Blindness Simulator
- Pick a colour from the swatch or paste a HEX / RGB value.
- Adjust the output — palette, contrast, complementary colours.
- Copy the value, or export the swatch as JSON.
When to use it
Common use cases include:
prepping images for web upload, e-commerce listings, social media platforms with format constraints, and converting files from one device or app to another.
Free vs Premium
Every visitor gets a free trial run; signed-in free users get a higher daily quota. Subscribe to
Premium
for unlimited runs, bulk processing up to 200 images per job, priority queue, and ad-free browsing.
Related tools
Looking for something slightly different? Try the
Color Picker from Image
,
Palette Extractor
or
Gradient Generator
— or browse all
Color Tools tools.
