Your skin produces a tan the same way it does when you tan indoors or outdoors. It is difficult to make a simple comparison of the sun with that of modern indoor tanning equipment. The sun’s strength is dependent on several factors as well. When you are outdoors in the sun you cannot control the amount of ultraviolet light you are exposed to. Indoor tanning is a very controlled environment in which you can regulate the amount of ultraviolet light you are exposed to. You can gradually increase your exposure time to achieve the tan you desire without burning.