Crafting an accessible site is a multidisciplinary task for sure. One of the things that designers can do early in the process is ensure readability. A big part of this is font size and color choices that are contrasty enough to read.
Here are two (Mac) tools that can help:
- Contrast A helps pick foreground and background colors that meet minimum contrast standards
- Frank DeLoupe gives you an eyedropper anywhere–awesome
I heard about both of these from Brad Frost and Dan Mall’s designer/developer workflow video.