Paper

Framing flat paper items

Conservation framing provides excellent protection for flat paper items against mechanical damage, dust, acids and the atmosphere. The frame forms a closed but not air-tight housing, allowing a slow interchange of air to take place but at the same time buffering the framed material against rapid atmospheric changes.

Framing is a very effective way of both displaying and storing flat paper items. But archival-quality framing is not cheap, and framed material takes up space; so paper items are often framed for exhibition, then unframed and returned to storage boxes.

Apart from the more valuable or popular items in the collection and works with their own frames, the items which benefit most from permanent framing are those which would suffer most from being left unframed—fragile or deteriorated items, works with friable media, and oversize works.

Poor-quality framing can do immense damage to paper items. It is therefore absolutely vital to ensure that items are framed to conservation standards.

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The major requirements for the correct framing of flat paper items are:

• the frame should be sturdy and its rebate should be deep enough to completely house the glass or acrylic glazing, the mounted item and a backing board. The rebate is the groove at the back of the frame;

• the item should always be separated from contact with the glazing by a window mount or by spacers;

• as far as possible, all materials used in the framing package should be archival. If you have to retain original material which is not archival, for example, mounts and backing boards you should insert a barrier of polyester or heavy-weight archival paper between the non-archival material and the item;

• because of the electrostatic charges that build up on acrylic sheet, glass should be used when framing any items which crumble easily. For example, pastel, charcoal, chalk or cracked paint, which is common with gouache; and

• the hanging devices should be sturdy. The frame should hang from two points on the wall, rather than hanging by a wire from one single point. D-rings hung from screws or hooks on the wall are suitable.

In special cases, the frame can be sealed to further isolate the item. Air-tight framing, or creating a sealed package within the frame, is sometimes used for travelling exhibitions or special items in a collection. This method reduces the flow of air, thereby reducing the effect of rapid environmental changes on the item. But it can also cause problems by creating an undesirable microclimate in the frame. Air-tight framing should only be undertaken by, or in collaboration with, a conservator.

If framed works are on extended display, they should be spaced away from the wall using small corks or plugs, to allow air circulation.

Glazing

When selecting glazing for a frame, it is important to note that:

• Acrylic sheet, Perspex, Plexiglas and polycarbonate sheet are light, unbreakable and can include UV absorbers. However, they cannot be used with fragile media susceptible to electrostatic charges; they are also easily scratched, and are more expensive than glass.

• Glass is more rigid. Glass treated to reduce reflected glare is available. If items are transported behind glass, the surface of the glazing should be gridded with masking tape: to reduce damage to the item should the glass break. Old picture frame glass can be more fragile than new glass, and it may be worth replacing it with acrylic sheet if the item is travelling.

The backing board

The backing board should be sturdy, reasonably lightweight and preferably archival. Archival corrugated boards made from paper or polypropylene, for example, Multi-Use Board, Corflute or Foam Cor Board are suitable.

If the backing board is not archival, for example, oil-tempered hardboard, an archival isolating layer should be used to separate it from the mount.

The backing board should be sealed with gummed paper or linen tape, to keep out dust.