Accession numbers

Accession numbers are serial numbers assigned to collection material at the time it was formally added to the library's collection. The earliest accession numbers at the Folger were based on purchase order line item numbers or on dates. Currently, a six-digit serial number is used. Accession numbers were not used by Mr. and Mrs. Folger, though their case numbers serve a similar purpose, as do "temporary" ART Inv. numbers.

Four-digit numbers

Four-digit purchase order numbers from the 1930s and 1940s are sometimes mistakenly labeled "ac" for "accession" in the card catalog. See the Collation post "Folger files; or a fetch-request come to life" for a particularly tricky example.

Six-digit accession numbers

The six-digit series began in the late 1940s with 125001 (because it was guessed the library already had about 125,000 things) but until 2004 the following material types instead received separate serial numbers: manuscripts (MS ADD), motion pictures (MP), video tapes (VCR), CDs (CD), CD-ROMs (CD-ROM), DVDs (DVD), phonograph records (p.r.), reel-to-reel tape recordings (t.r.), and cassette tape recordings (t.r.c.).

Accession slips numbered lower than about 200000 were often typed based only on the title page, without checking for completeness or additional information (e.g., a colophon).

Six-digit accession numbers for sammelbands do not represent a specific title. Instead, titles within the volume have accession numbers with decimal points: six digits, a decimal point, then 1, 2, 3, etc. In most cases, .1 is the first title in the volume, .2 is the second, and so on. However there are early accession numbers (lower than about 200000?) where only the titles not already in the collection received an accession number and typed accession slip.

There are gaps in the numbering thanks to numbers kept in reserve not being needed (e.g. 245001-245999 were reserved for the Massey collection, but only 245001-245326 were needed; 245901 and 245902 were assigned to non-Massey material by accident; the rest of the reserved numbers remain unused).

These groups of six-digit numbers are known to be not unique:

• 156481-156509 were used twice: second series has "[2d]" after the number.
• 207168-207226 were used twice: vault books have just the number, modern books have the number followed by "[2d]".
• 222701-222744 were used twice: second series has "[2d]" after the number (222701-222800 were reserved for the Colt collection, but there turned out to be more books than expected, so they re-used the first 44 numbers rather than jumping ahead to the next available number).
• 226884-226893 were used twice: vault books have just the number, modern books have the number followed by "a".

Note: accession slips are filed in two series; books on the shelf are interfiled.

Until 2002 all Mazarinades received accession no. 134829 and all Knuttels received accession number 143966.

Some open-stacks books no longer receive accession numbers (as of 2009?). E.g., YBP books with vendor-supplied cataloging and processing are considered "shelf ready."

Accession numbers in Folger MARC records

The Folger started creating MARC records in the 1980s (in RLIN, to be printed out on cards), and in the years since, accession numbers have ended up in various fields and subfields. This is an attempt to list them all. Please add to the list as you discover them.

Important: numbers in these fields are not necessarily accession numbers.

Note: some 6-digit accession numbers are prefaced with "ac" or "F"; if you come across such a thing, delete the preface. Do not delete the "cs" that precedes case numbers.

• 050‡f
• 090‡f
• 099‡a (current practice: Acquisitions puts accession number in 099‡a)
• 099‡f
• 852‡h (not really an accession number: catalogers construct "accession-based" call numbers" in the ‡h, converting the accession number to a call number by adding "hyphen space" in the middle, and a lowercase letter for shelving type at the end; sometimes "space hyphen" or just "hyphen" or "space hyphen space" was added instead).
• 852‡j ('current practice: Cataloging enters accession number in the 852‡j when items are dispersed).
• 852‡x (see example).
• 950‡q
• 955‡q

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