Color Blindness Simulator
Preview how designs appear to people with different types of color vision deficiency.
Color Formats Supported
- HEX: 6-digit hexadecimal codes (#FF5733)
- RGB: Red, Green, Blue values (255, 87, 51)
- HSL: Hue, Saturation, Lightness (11°, 100%, 60%)
- CMYK: Cyan, Magenta, Yellow, Key for print
Using Colors Effectively
1. Accessibility: Ensure sufficient contrast for text readability 2. Consistency: Use a defined palette throughout your project 3. Hierarchy: Use color to guide attention and establish importance 4. Brand: Maintain consistent colors across all materials
Color Theory Basics
- Primary colors: Red, blue, yellow (can't be mixed from other colors)
- Secondary colors: Orange, green, purple (mixed from primaries)
- Warm vs Cool: Warm colors (red, orange) feel energetic; cool colors (blue, green) feel calm
Designing for Colour Vision Deficiency
About 8% of men and 0.5% of women of northern European descent have some form of colour vision deficiency. The distribution is not even:
| Type | Affects | Prevalence (men) |
|---|---|---|
| Deuteranomaly / deuteranopia | Green perception | ~6% |
| Protanomaly / protanopia | Red perception | ~2% |
| Tritanopia | Blue perception | <0.01% |
| Achromatopsia | All colour | ~0.003% |
The rule that fixes most of it: never encode meaning in colour alone. Add an icon, a label, a pattern or a position. A chart with a legend that only distinguishes series by colour is unreadable for one reader in twelve; the same chart with direct labels is readable by everyone.
A Full Ramp From This Colour
Design systems settle on a 50–900 scale because it covers backgrounds, borders, text and states without anyone reaching outside the palette. Mixing toward white and black rather than adjusting HSL lightness keeps more of the hue's character:
| Step | Colour | Contrast on white | Safe for |
|---|---|---|---|
| 50 | #F5F9FF | 1.06:1 | backgrounds and fills |
| 100 | #EBF3FE | 1.12:1 | backgrounds and fills |
| 200 | #CEE0FD | 1.34:1 | backgrounds and fills |
| 300 | #B1CDFB | 1.62:1 | backgrounds and fills |
| 400 | #76A8F9 | 2.40:1 | backgrounds and fills |
| 500 | #3B82F6 | 3.68:1 | large text, borders |
| 600 | #326FD1 | 4.85:1 | body text on white |
| 700 | #295BAC | 6.59:1 | body text on white |
| 800 | #204887 | 8.98:1 | body text on white |
| 900 | #183462 | 12.31:1 | body text on white |
Adjusting It
Base colour in HSL is hsl(217, 91%, 60%). Two useful moves:
``css
/* +10% lightness, same hue */
--lighter: #6da2f8;
/* −10% lightness */
--darker: #0b64f4;
``
Raising lightness also drops perceived saturation, so a lightened colour reads greyer than its numbers suggest. Adding 5–10% saturation alongside every 20% of lightness keeps the ramp looking like one hue rather than a fade to grey.