WCAG Colour Contrast: What does the 4.5:1 ratio actually mean?
Ever wondered why WCAG sets a minimum contrast ratio of 4.5:1? It’s not just a random number - it’s based on how our eyes perceive brightness and what makes text readable. Let’s break down the science of colour contrast, relative luminance, and why good contrast benefits everyone. From early accessibility research to how different colours contribute to brightness, we’ll explore what these ratios really mean - and why they’re essential for legibility in all conditions.