Because Archivalware's specially formulated 3 mil archival polypropylene has a physical density that is less than other sleeving materials, it is more pliable and gentle to your film. Strong and durable, Archivalware won't become brittle or abrade film. Archivalware sleeving is optically clear, color neutral, and has a unique anti-Newton ring surface that reduces distracting Newton rings as well as minimizing the actual surface area that is in contact with your film.