The types of restrictions on collection material are:
Restricted fragile (Section 4.6.1). Used for material that is too fragile to be used for research, and for open format audiovisual recordings. Exceptions require curatorial approval.
Restricted access (Section 4.6.2). Formerly used for audio and video cassettes, which cannot be accessed by researchers, but are not considered restricted fragile.
Restricted papers (Section 4.6.3). Used for material restricted for reasons of privacy, usually at the request of the donor.
Restricted duplication (Section 4.6.4). Used for materials that can be accessed for research, but not duplicated. This type of restriction is rare.