The 3M films have their UV absorbers incorporated into the adhesive. Previous studies (2, 6) have indicated that this is less desirable than having a separate UV-blocking layer, leading
to worse performance and longevity, but no experimental support has been given for this assertion. Our findings show that the 3M films performed more uniformly well than any other brand, despite having UV blockers in the adhesive; the second part of the study will evaluate their longevity.