Five mistakes teams make with colour contrast

We end up explaining this on discovery calls often enough that it deserved writing down. These are the ones we run into repeatedly when we audit colour contrast.

Design decisions are the ones clients feel most confident arguing about, which makes it worth separating taste from evidence early. If it only works because one person remembers to do something, it does not work yet.

Common failure modes

• Treating it as a launch task rather than an ongoing one
• Assuming someone else already owns it
• Body text needs a 4.5:1 contrast ratio against its background
• Light grey on white fails more often than designers expect
• Never checking whether the fix actually worked

Contrast checkers take seconds and settle arguments. In practice this is a scheduling problem more than a technical one. Anything you cannot measure here, you are deciding by taste, which is fine as long as everyone knows it.

Making it stick

The short version

The measurable part of design is whether people can find what they came for and act on it without hesitating. Three things worth confirming about colour contrast before you move on:

• Someone can say what the current setup is without going to look
• Contrast checkers take seconds and settle arguments — 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.