What sun protection factor lotion should black people and other very dark-skinned people use?

SPF: There's a perception that people with darker skin don't have to worry about skin cancer, but that's not true. Minorities do get skin cancer, and because of this false perception most cases aren't diagnosed until they are more advanced and difficult to treat. Use an spf of 30.

Same as white people: Dark-skinned people get skin cancers too, though not as often as light-skinned people. Wear the highest spf you can lay hands on, but no less than spf 15. And make sure to re-apply when you get wet from swimming, sweating, etc. Some of the sprays are very convenient and provide excellent coverage. Sunscreens also retard the development of wrinkles, which is a nice plus.