Object Numbering and Object Marking

All of the National Trust Historic Sites maintain a museum collection of some kind.  Some sites have a very large museum collection (such as Villa Finale, with over 12,000 objects), while other sites have a very small collection (such as Farnsworth House, with fewer than 100 objects), but all Sites have collections that need to be tracked and protected.  Following is an overview of object numbering and object marking at National Trust Historic Sites.

Object numbering refers to which type of numbering system is appropriate to track a particular object.  Object marking is the physical application of an accession number (or other kind of number) to the object.

Numbering systems – accession numbers

The National Trust is the owner of museum collections at 20 of the 29 National Trust Historic Sites and the Headquarters building in Washington, DC.

As a general rule, all accessioned objects owned by the National Trust– accessioned objects being objects in the museum collection that are assigned the highest level of care and oversight– are numbered in the year/accession/object style:

NT 2010.1.1

Child's chest of drawers

For example, the number above refers to the 1st object in the 1st accession (in this case, a gift) in the year 2010.  The first gift of the year in 2010 was a child’s chest of drawers, previously owned by Nelly Custis Parke Lewis, to Woodlawn.

For most of the National Trust’s history, a two-digit year numbering system was used instead:

NT 69.38.245

This number refers to a bronze maquette of “Harvest”, by Daniel Chester French, in the collections of Chesterwood, French’s home and studio in Stockbridge, Massachusetts.

"Harvest" by Daniel Chester French

The NT 69.38 accession number was assigned to all objects in the bequest of Margaret French Cresson, Daniel Chester French’s daughter, to the National Trust– this “Harvest” maquette being the 245th object in that bequest.

The numbering system changed from a two-digit year to four-digit year in the 1990s, in recognition that object numbers would begin to duplicate if the two-digit year numbering system was maintained in perpetuity (how could you know if the object number NT 59.3 refers to 1959 or 2059?).

Gifts to, and purchases for, National Trust-owned collections at all National Trust Historic Sites are processed through the National Trust Headquarters office.  National Trust accession numbers are assigned from this office sequentially throughout the year, in the order in which the gifts and purchases are completed.

Numbering systems- loans

Loans to and from National Trust Historic Sites also are assigned tracking numbers.  The general style of Loan numbering is:

L 1.2010.1-6

This number was assigned to the 1st loan in 2010, which was a loan of 6 textiles from the Woodrow Wilson House to the Edith Bolling Wilson Birthplace Foundation and Museum.

Assigning numbers to Objects Found in the Collection

At times, colleagues at National Trust sites encounter objects in their collections that are unnumbered, cannot be matched quickly to any existing documentation, or otherwise have a mysterious provenance or history. 

In such cases, research needs to be undertaken to try to identify if the object is a loan (particularly one that may have been forgotten by the owner); a gift offer that was never completed; a personal item left behind by a previous staff member or other visitor to the site; or another possibility. 

Until more is known about an object, it is helpful to assign these objects a temporary tracking number.  A tracking number allows staff to maintain intellectual control over these objects while still allowing flexibility for future research, or, ultimately, the ability to assign accession numbers at a later date if appropriate.

 Tracking numbers for objects found in the collection should be assigned as follows:

 X.[Site Initials].[Four Digit Current Year].[Sequential Number]

So as an example, if a group of “mystery” objects are found at Lyndhurst in the year 2011, they would be assigned the numbers X.LY.2011.1, X.LY.2011.2, etc.

Physical Object Numbering

Once an accession number has been assigned to an object, it is standard museum practice to physically apply the number to the object.

The manner of applying an accession number to a museum collection object depends on various factors, such as the medium (the material composition of the object), size of the object, fragility of the object, and so on.

A common way to number museum objects has been to follow the following steps:

1) apply a clear basecoat (while some people may colloquially refer to this as “clear nail polish”, actual nail polish is not recommended; a standard material used is the acryloid B-72 clear lacquer)

2) paint or otherwise apply the number

3) protect with a final topcoat of B-72. 

An excellent overview of the use of B-72 in object marking can be found in this Conserve O Gram by the National Park Service.

There's no missing the accession number painted in large, white numbers on this clock

There is a wealth of information easily available on object numbering in standard museum reference sources.  An excellent overview is provided in the “Marking” section of the seminal text Museum Registration Methods 5th Edition, Rebecca Buck and Jean Gillmore (Editors), published by the American Association of Museums.  Another helpful resource is the Illinois Association of Museums has produced this very helpful pamphlet How to…Mark Objects in Museum Collections.

Two National Trust Sites have provided an overview of their object numbering techniques.  Meg Nowack, the Manager of Curatorial Resources at Villa Finale, has prepared a short video on object cleaning and marking, which can be accessed via the Villa Finale website, or by following this direct link.  Interns at President Lincoln’s Cottage prepared this blog post about their experiences with object marking from the summer of 2008.