Numbering Collection Items

Image from 'A behind-the-scenes look at our butterfly collection'.

During the accession process, it is important to mark each object with a unique identification number (accession number aka registration number), which will link that object to the museum’s documentation.  Because the number is vital to managing the object effectively, it must be applied in a way that is long lasting.  It is equally important that applying the number does not damage the object in any way.  Each type of object needs a different approach, according to the materials from which the object is made.  In order to do this, some special equipment is needed.

Procedure

Each object is marked in an inconspicuous but accessible place with its accession number.  It is important that the method of marking is durable but removable and must not be damaging to the object.  For instance, sticky labels can leave an adhesive residue, which can cause damage. 

• Choose a suitable but discreet place on the object that is not visible when the object is on display but visible enough to identify the object with minimum handling.  Try and develop regular places where you put numbers on similar objects, e.g. base of glasses and cups, rear right-hand corner of furniture or machinery, waistband of skirt or trousers.
• For most objects the surface selected for numbering is prepared by wiping with a clean dry cloth or cleaning with a cotton bud dipped in methylated spirits, only if the object needs cleaning.  Glass, ceramic and bare metal objects are usually fairly safe to clean with methylated spirits.  This removes surface dirt and grease and makes it easier for the varnish and ink to “take”.  However, avoid using it on painted, varnished, plastic and wooden surfaces, and do not use on paper or textiles. 

Materials for numbering objects

Varnish/base coat:

For robust objects made of ceramics, metals, plastics or wood, a semi permanent system of applying a base coat of varnish, then an inked number, topped by a protective coat of varnish is widely used in museums.  Remember to allow the ink to dry before applying the top coat of varnish.  The base coat of varnish protects the surface of the object from the ink used to apply the number, as well as providing a suitable base on which to apply a number on porous or rough surfaces. The topcoat protects the ink number from being rubbed or worn.  This process of semi permanent numbering ensures a robust identification system without damaging the object. 

Do not use tippex/liquid paper or clear nail polish.  The recommended varnish is Paraloid B-72 (mixed in white spirits or acetone).  This can be used on wood and metal and is easily removed using acetone.  Paraloid B-67 in bead form (dissolved in acetone) can be used on plastics and can be removed with white spirits.  These products are available from conservation materials suppliers. 

Pens

The following are suitable for all numbering, data sheet and register entries:

• Rotring Isograph 0.25 or 0.35, using India or technical drawing ink
• Uniball Micro Deluxe (black)
• Artline Drawing System (no.17) 0.4 - 0.1
• Pentel Document pen permanent MR 205 Black (no.19)

Inks

Specialised Waterproof India or technical drawing ink, used with a fine dip pen (0.35 mm) or Rotring Isograph pens are suitable for marking the number on the varnish base coat.  For numbering dark coloured objects, use a white ink (tinta china).

Pencils         

Soft 2B pencil for all paper materials and photographs on uncoated base paper

Stabilo All Pencil 8008 A11 can be used for marking on resin coated papers and negatives.

Apply the number on the back inside cover of a book and the back upper or lower right corner of documents and photographs.  Framed paintings and photographs should also be numbered on their frames, as reframing may occur at a later date. Use pen ink and varnish to number the frame.

Sewn labels

Do not apply a number directly to a costume or textile object. Using a black pen as mentioned above, the unique identifying number should be written on to white cotton tape (6mm width), and sewn to the object using black/white cotton or silk thread.  Stitch it carefully into the seam or other strong part of the object, e.g. the right shoulder seam on dresses and blouses, the mid-back waistband on trousers and skirts, stitching with a ball point needle between the threads of the textile to minimise damage.

Tied labels

Tags can be used to label objects if it is not possible to apply a semi permanent number. Marked objects should also be tagged in storage, making it easier to locate and identify the object without too much handling.  Items awaiting acquisition assessment should also be labeled with a tag.  When using tags it is important to use archival quality tags and cotton tape or string for attaching, taking care not to damage the item in any way.

Gloves

Gloves are used in museums to protect objects and maintain conservation standards.  White cotton gloves should always be used for handling metals, textiles, mixed media objects, and other delicate items and are available from photograph processing shops.  Surgical gloves (available from chemists) should be used when handling objects made of glass or ceramics.

Tape measure

A soft metric tape measure with metal ends removed is useful when documenting an object’s dimensions during the process of cataloguing the object.

References and further reading:

Museums Australia Inc (NSW), Museum Methods, A Practical Manual for Managing Small Museums, Collection Management, 3.6 Numbering objects in museum collections, 3.4 Cataloguing museum collections

Heritage Collections Council, ReCollections at the Australian Institute for the Conservation of Cultural Material (AICCM) website

Museums and Galleries NSW, Online Resources, in particular Acquisitions Fact Sheet 

Collections Trust UK Collections Information Standards: Linking Objects to their Information