What do you do when a brand color fails contrast without changing the brand?

The 1.4.3 Contrast (Minimum) criterion says "Text that is part of a logo or brand name has no contrast requirement." The Understanding page draws the line at logos: "Beyond logos and logotypes, text that has insufficient contrast due to corporate identity or brand guidelines is not exempted from the requirements of this criterion." A brand color on a link, a label or button text therefore has to pass. A filled button or icon also falls under 1.4.11 Non-text Contrast when its color is the only visual sign that the control exists.

Start with a blue, #4A90E2. On white it reaches 3.29:1, which misses 4.5:1 for normal text but clears 3:1 for large text and for a fill that needs 3:1. Keep it as a fill and put near black #1A1A1A text on it. That pair reaches 5.29:1 and passes for normal text. White text on that fill reaches 3.29:1, which misses 4.5:1 for normal text. For text and links on white, use a darker shade of the same hue. Both blues sit at a hue of about 212 degrees. #2F6DB5 reaches 5.28:1 on white and passes for normal text.

A brand orange like #FF6B35 fails even the 3:1 bar on white, at 2.84:1. The fix, #C2410C, reaches 5.18:1 on white, and white text on it gets the same ratio, so both pass 4.5:1. The two oranges sit at hues of 16 and 17 degrees, which is nearly the same hue. Yellow works better as a fill than as text. #E8A317 reaches only 2.17:1 on white, but #1A1A1A text on it reaches 8.02:1, which clears the 7:1 AAA level.