019 The COLIPA Standard for solar simulators failed to standardize sunscreen SPFS

The COLIPA Standard for solar simulators was developed to insure that SPF tested in different laboratories was not different because of the solar simulator used. Indeed for products with lower SPFs 2-10, the solar simulator standard reasonably assures similar SPFs when tested in different laboratories. For products with SPFs greater than 15, the SPF for the same product could be tested at 15 in one laboratory but as an SPF 100 in another. Differences in SPF due to solar simulator filtration will occur only for sunscreen products that exhibit absorption like cut-off filters. Products which generally absorb all UV wavelengths equally will not exhibit differences in SPF due to solar simulator filtration. In addition because of different amounts of UVA allowed within the COLIPA standard, the actual response for a given exposure may in one laboratory produce persistent pigment darkening and in another a simple sunburn. Ways to correct this flaw will be examined.