Is white or black clothing better for sun protection?

While it is common knowledge that light clothing is better for this, I understand that it is best t keep you cool. I don't care that much about being cool, but I hate tanning, hate sunburns, ad I'm scared as hell of skin cancer. I don't want to be cool, but want actual protection. My studies tell me that dark clothing absorbs more UV rays and converts the into heat, making you hotter, but also that dark clothing has a higher SPF (sun protection factor) value, which I'm guessing is resulting from them absorbing the rays. So, staying cool aside, I would like to know what is best to wear to avoid actual damage from the sun. Also, I normally wear a T-shirt with a long-sleeve button-up over it, so if I should dress in a way that involves me wearing two different colored shirts, then I am willing to do so to be protected. I also wear clothing that is made almost entirely of cotton, so no worries about that. My favorite colours are black and white, so I'd prefer to dress that way. Remember, I don't want to stay cool, I want to avoid solar damage to my skin. Thank you!