I would like to know what is the difference between natural medium brown hair color and rich medium brown hair color?
Also... is medium rich brown darker that natural medium brown?
Thank You

The only way to know would be to look at samples of each. Is there a certain brand you're looking at?

Color names are really not much good in determining color. As the say, "The proof is in the pudding.". What it looks like on you is the important thing. Both the medium brown and the natural brown will look different on people with slightly different natural haircolors.