SPF is a compromise for the sun gods

NEW YORK (AP) -- People love sun, people worship sun and sometimes people need sun.
But that doesn't mean the sun is ever good for skin, says Dr. David Orentreich, a consulting dermatologist for Clinique.
There is no harmless amount of sun exposure for the skin, according to Orentreich, since even small amounts of exposure to ultraviolet rays can contribute to photo-aging and possibly skin cancer.
Orentreich, though, acknowledges that medical studies have linked sun and light to psychological well-being.
The keys to balancing physical and mental health when it comes to sun exposure are moderation and sunscreen, used properly, of course.
Orentreich debunks some sunscreen myths:
UOnce burned, you cannot just reapply sunscreen and go back in the sun. Skin should not be re-exposed to the sun -- even with sunscreen -- until redness has disappeared.
U The level of SPF multiplied by the amount of time it takes to burn without sunscreen equals the minutes of protection that you will get by using that level of sunscreen.
For example, if it usually takes 10 minutes to burn in the sun without using sunscreen, you will get 150 minutes of protection by using SPF 15.
UPeople with darker skin do have more natural protection against UVB rays but they still need UVA protection.
Orentreich recommends an SPF range of 15 to 30 for both light and dark skin.