Often the choice of whether to use glass or acrylic when framing is simply one based on personal preference. Some prefer the clarity of glass, while others would rather not risk the possibility of breakage and will choose to use acrylic. Acrylic is also lighter weight, which can be a factor with oversize frames. Both materials can be purchased standard or with UV protective coating. Acrylic, however, has static qualities and should not be used with charcoal, pastel, or any medium that is has particles that may pull loose from the surface of the paper. Whatever the choice of material, be sure to clean the inside surface carefully before closing the frame to avoid trapping any particles.