TO TRACK MUSEUM collection objects—to differentiate between permanent, on-loan, and subsidiary collections, and most important, to provide access to the documentation of objects in a collection—it is vital that a systematic numbering scheme be used. The numbers assigned to objects are marked on most permanent collection objects, tagged onto objects in temporary custody, and prominently noted on all documentation associated with the objects.
Museums have tried many numbering systems over the years (BOX 5A.1). The most important thing about a number, whether permanent or temporary, is that it be unique because it is the link between the object and its documentation. Without a unique number an object is at risk of losing its context and information relating to its legal status. Sequential numbering (1, 2, 3, 4), based on early library accessioning systems, is simple and has been used by many museums (it is the current standard in most natural history collections). The system is simple—the first object gets number 1, the second object is number 2, and on into infinity. Simple sequential numbers do not show what the relationship is between objects (e.g., year of accession into the collection) so many museums choose a two-part system that incorporates the year of accession and an object number (e.g., 76.21-27, 1976.28). Simple sequential series have the advantage that sequential numbers are far easier to transcribe (particularly when entering them into an electronic database) and mark on objects without error; it is far easier to write 69482 correctly than 2019.12.342. The two-part system has the advantage of communicating some information about the object (e.g., year of accession), but the numbers are more prone to transcription error and can be long to mark on small objects as well as receipts, deeds of gift, warranties of title, etc.
BOX 5A.1 COMMONLY USED NUMBERING SYSTEMS IN MUSEUMS*
| Description | Number | Definition |
| Permanent collection, legally owned objects; compound numbers | 2010.1 | First transaction of trie year 2010 |
| 2010.1.1 | First object is a single unit | |
| 2010.1 .1.1-10 | First object is a set often pieces | |
| 2010.1.1a, b | First object is a pair, two parts | |
| Suggestions for temporary records, short and long-term loans | TR1.2010 | Transaction, first of year 2010 |
| TR1.2010.1 | First object in trie transaction | |
| L.2010.1 | First loan of trie year 2010 | |
| L1.2010 | ||
| L2010.1.1 | First object of first loan of trie year 2010 | |
| Ll.2010.1 |
*Museums may also develop numbers for long-term loans to differentiate them from exhibition loans, and for long-term incoming loans. Supplemental collections may have yet another number. It is always best to keep numbering systems to a minimum and to keep them as simple as possible.
An argument can be made that there is no need for an object number to carry information because that information is recorded elsewhere; instead, the number should be simple to use and easy to transcribe. In the end, what is most important is that the number system in use be consistent. If a collection has not yet been numbered, it is worth pondering the pros and cons of simple sequential series, but if the numbering system has been in use for some time—particularly if information about the objects has been published using their object numbers—it is probably best to retain the old system.
The use of electronic databases can overcome most of the difficulties caused by various early numbering systems, as long as every number used is unique (but computers can also multiply human mistakes at an astounding rate). For example, it is possible to impose a transaction number on sequential or separated objects and pull them together in a database. If 21.3-10 and 21.15 are found to both be from the same transaction, the registrar can review the year and systematically assign a transaction number to which all pertinent object records can be attached (e.g., 1921.3).
Systems with alphabetical prefixes are popular, but they can become cumbersome if the prefix refers to a collection category, a geographical location or a department. Any of those categories may become obsolete or inaccurate with the renaming or reorganization of the referenced categories. A prefix may, however, be useful for loan collections, temporary custody, or for subsidiary collections used for teaching purposes, but is not recommended for permanent collections (BOX 5A.2).
Museums with several numbering systems may find that the systems become confused. Some museums have found it helpful to retire old, complicated systems and implement a single standard system, but in general it is inadvisable to attempt to renumber a large permanent collection (and in any case, it is likely to induce many errors). A single system applied from a certain date forward will simplify recordkeeping for current and future activity. Attempts to renumber almost always end in chaos.
BOX 5A.2 PREFIXES GONE WRONG
| Number prefix | Possible meanings |
| C | Cambodia, Ceylon, coins, crosses |
| P | Painting, Persia, Peru, Portugal, pottery |
| S | Science, sculpture |
It is important to be consistent in numbering once a preferred system has been selected. Separate numbering systems must be available for objects in temporary custody and permanent holdings, and each system must have its own sequence. If several departments use different systems, they must communicate and make certain that their systems do not overlap and create duplicate numbers. Because collections management databases usually use the assigned number to identify a record about an object duplicate numbers will lead to confusion.
Old numbers arise in collections in a variety of ways—a change in the scheme used to number objects, the acquisition of a collection assigned numbers by a previous institution, or unintended duplication within a collection. It is important that old numbers be kept as part of the institutional history of an object. However, the old number should be physically removed from the object (if it is possible to do so without harming the object) and the new number applied (see CHAPTER 5F, “Marking”). Most collection management systems have a field that allows for tracking old numbers that should be used to keep track of any old number associated with an object. These numbers will likely be referenced in old documentation, publications, catalogs, and files, so keeping old numbers associated with the object aides in tracking its whole history. Additionally, both the old numbers and the new numbers now assigned should also be recorded in any acquisition files.
A numbering system for objects in temporary custody helps track objects and associated documentation until the objects are accessioned and or returned to their owner. The temporary number may be structured in parallel with the accession number system, as described here, or may bear a T (Temporary,) TR (Temporary Record), or other prefix (L for loan, E for exhibition, etc.) to distinguish it. Some institutions chose to use what amounts to an accession number in reverse, that is, “16.1996” instead of “1996.16.”
Perhaps the accession numbering system most widely used in the United States is a compound number separated by a point or hyphen. In this system, the first number indicates the year the object is accessioned and may be the whole year (1995) or a part year (995 or 95). The whole year is recommended to avoid confusion in the future (and if it was not used in the past, it should have been started with the year 2000). The second number indicates the sequence of the accession by which the object was formally taken into the collection such that 1995.1, 1995.2, and 1995.3 indicate the first three accessions of 1995. If there is only one object in the transaction, the two-part number typically suffices (this is common in art museums). If more than one object is included in the accession, a third number is usually assigned to each object, as in 1995.4.1, 1995.4.2, 1995.4.3. If an object is a set, portfolio, or consists of several parts, the number may have four parts (e.g., 1995.4.3.1, 1995.4.3.2). To identify component parts of an object (such as a box with a lid, a chest with removable drawers, a sculpture that can be disassembled, or a tea set) some museums prefer to use alphabetic suffixes such as 1995.4.3.a, 1995.4.3.b, etc. (see BOX 5A.3).
BOX 5A.3 EXAMPLES OF THE STANDARD NUMBERING SYSTEM
| Portfolio of eight photographs | 1997.1.1.1-8 |
| Six separate photographs | 1997.1.2-7 |
| Coffee pot with tray | 1997.1.8a-c (pot, cover, tray) |
| Painting | 1997.1.9 |
| Pair of shoes | 1997.1.10a, 1997.1.10.b |
| Single object purchased | 1997.2 |
In a compound numbering system in which each separate object has its own distinct identification through the accession number, the transactions for each year can be easily counted. The system allows for growth because each year starts with transaction 1 and ends with the last transaction of the year. Future research that changes the intellectual classification of objects will not interfere with the number. If an object was overlooked during initial accessioning, it can be added later at the end of the sequence for an individual transaction. Number systems that use an alphabetic or numeric identifier for the objects category, site of origin, or some other information (e.g., 1995.A4.3.1 for an object from the art collection, 1995.F4.3.1 for an object from the furniture collection) can be useful but make it difficult to reclassify objects and create numbers that make transcription more problematic.
BOX 5A.4 THE NUMBERING RACKET
One of the best ways to ensure that numbers are not duplicated is to use a standardized system. In the first edition of Museum Registration Methods (published in 1958), Dorothy Dudley and Irma Bezold described object identification numbers in the broad context of their use for accessions, extended loans, or loans for exhibition. There was a reference to a type of catalog number they called a curatorial number. By the third edition (1979), however, the glossary compiled by Patricia Nauert was specific in differentiating between the two, defining an accession number as “a control number, unique to an object, whose purpose is identification, not description,” and a catalog number as
a term used in a variety of ways in museums: (1) in some museums, a catalogue number is assigned to an object or specimen based on its class; its purpose is description; (2) in some museums, the number described in this book as an accession number is called a catalogue number, in which case its purpose is identification; (3) the number assigned to an object in a printed publication or catalogue of a special exhibition or collection.
In some types of museums, most notably archaeology and natural history museums, a single accession number is applied to all of the objects received at the same time from the same source, which may be a single object, dozens, hundreds, or thousands of objects (BOX 5A.4). Rather than mark individual objects with an accession number (which would result in many objects with the same number), the individual objects or specimens are marked with catalog numbers. Thus, an accession number (e.g., 1995.13) may be assigned to a group of 310 specimens of frogs collected on a single expedition to Peru in 1995, but the individual specimens in the accession will be numbered sequentially as 69012, 69013, etc. The accession record would indicate that it included specimens numbered 69012-69322 in the catalog.
Registrars are often faced with an array of unprocessed material from the near and distant past (see CHAPTER 3J, “Found in Collection”). To track these objects, it is recommended that they be assigned temporary numbers until their status is clarified.
Title must be transferred to a museum before an object can be considered part of the permanent collection and accessioned; thus, objects on loan are not part of the permanent collection and should receive temporary numbers for tracking (or better, use the number on the object from the loaning museum). Up until the early to mid-nineteenth century it was not uncommon that all objects coming into the museum—loans, gifts, purchases, bequests—were considered accessioned because accessioning was more about tracking than it was about the permanent collection. In current museum practice, only objects that are owned by the museum are accessioned into the permanent collection (see CHAPTER 3B, “Acquisitions and Accessioning”). •
This chapter has been edited and updated from previous chapters by Rebecca Buck with thanks to Anne Furhman Douglas, Connie Estep, Monique Maas Gibbons, Paulette Dunn Hennum, Kittu Longstreth-Brown, and Dominique Schultes.