FOR THE PAST 2 YEARS we have been clinically evaluating a new topical agent which produces a light filter in the skin. This filter has the following advantages and characteristics: It absorbs 95% of the total ultraviolet (UV) and 20% of the infrared radiation reaching the skin. It is chemically bound to the skin; therefore, it can not be washed off and it need be renewed only every day or two to give protection from light in the majority of sunlight sensitive patients. Since the filter does not completely block out all UV radiation, the skin can acquire a natural tan but at a slower rate than normal. It is cosmetically acceptable in that it produces a natural brown color in the skin as a result of the chemical reaction between the application material and the keratin. The agent can be applied to the skin in a grease base, a