How to make microscopy images that are color blind friendly

These days, there is increased awareness about color blindness (also known as color vision deficiency) and figure accessibility. During peer review, referees are now more likely to request changes to color palettes in papers to assist color blind readers. This is a positive change, and of course it is best to check that our images are accessible. However, it is less useful when referees reflexively request changes because they believe that certain color combinations should be 'outlawed' for reasons of accessibility. What I mean is: some scientists believe that all red-green-blue overlays are fundamentally bad for accessibility. In this short Essay, I try to set out why that view is misguided and to provide some practical solutions to the problem.