Colour contrast: what to get right first

Teams tend to reach for this after something has already gone wrong. If you only fix one thing about colour contrast this quarter, make it the first item below.

The measurable part of design is whether people can find what they came for and act on it without hesitating. If two people in the business would answer this differently, that gap is the actual problem.

Start here

Body text needs a 4.5:1 contrast ratio against its background. That sounds obvious written down. It is still the thing most often skipped. Assume whoever inherits this will have half your context and none of your patience.

Then this

Light grey on white fails more often than designers expect. Where this goes wrong is almost never a lack of knowledge. If it only works because one person remembers to do something, it does not work yet.

Eventually

Contrast checkers take seconds and settle arguments. Small and consistent beats large and occasional here. The failure mode is not doing it wrong, it is doing it once and assuming it stays done.

How to tell if yours is fine

Design decisions are the ones clients feel most confident arguing about, which makes it worth separating taste from evidence early. Three things worth confirming about colour contrast before you move on:

• Someone can say what the current setup is without going to look
• Light grey on white fails more often than designers expect — and you know whether that is true here
• There is a way to tell whether the last change to this helped

If you are not sure where your systems currently stand on this, it takes us about an hour to find out.