Spectrum shows how an image looks to people with different kinds of colour-blindness — red-weak, green-weak, blue-weak and full greyscale — side by side with the original. A quick way to check that a chart, UI or design doesn't rely on colour alone. Your image never leaves your device.

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JPG, PNG, WebP · stays on your device

The simulations use standard LMS colour-space matrices for the three common types of colour-blindness (protanopia, deuteranopia, tritanopia). They approximate how colours shift, not a medical diagnosis. If a design still makes sense in greyscale, it doesn't depend on colour alone. Everything runs on your device.