What about the mat color?
The idea of using a mat with your piece of art is to focus attention to the artwork as well as separate it from the glass. When you choose the color of the mat it is best to use moderation. You want the artwork to take center stage. You don’t want your eye to go out to the mat. A white value that isn’t too bright looks good with almost anything. There are many whites to choose from. Other soft colors pulled from the colors found in the artwork can be chosen as well.If the art is almost entirely white you can consider mounting with a gray or black mat for some drama.
If you want a burst of color, keep it to the second mat underneath and show only 1/8 inch so attention isn’t drawn away from the artwork but just enhances. This accent mat isn’t necessary but does add a decorative touch.
Another decorator’s touch is to use a triple mat all in a cream or off–white.