Flat files provide a good short-term solution for storing finished, unmatted charcoal or pastel works on individual sheets. In this case, a sheet of acid-free glassine interleaving (similar to tracing paper) should be placed between each piece. For the long term, however, it’s much safer to mount and mat these works. The mats act as spacers, preventing the dry pigment from coming in direct contact with any other surface.
Archival Storage Boxes