In this context "special collections cataloging" means fuller use of notes, access points, and other elements that are not specifically called for in AACR2 or its predecessors, but that follow the spirit of DCRM(B) without following its rules completely.  Such cataloging is frequently done for 19th-century and later materials housed in special collections.  Do not apply the code "dcrmb" to records for "special collections cataloging" unless the cataloging follows the descriptive requirements of DCRM(B) completely (full, core, or minimal level).

See also:

Appendix A:  MARC 21 Descriptive Conventions Code