What is conservation framing?

A mount and frame should always be selected to protect as well as enhance a picture. Unfortunately, some mounting and framing techniques not only fail to protect, but are potentially damaging to works of art. ‘Conservation framing‘ is a term used to describe the use of materials and techniques which provide protection to framed works of art on paper. There are different levels according to the quality and specification of the materials used.

Why do works of art on paper need protection?

Paper is sensitive to its surroundings: it can be adversely affected by damp, changes in temperature and humidity, restriction of movement and exposure to light. Paper will also react to the materials with which it is in contact such as acidic support boards and self-adhesive tapes. Evidence of damage caused by adverse conditions can be seen in pictures with mount burns, foxing (small brown spots), fading of pigments or darkening and increasing brittleness of the paper.

Preparing a picture for framing

If the picture is damaged, foxed, stained or stuck down onto an acidic card backing, a paper conservator can advise on preservation and conservation options. In some cases, preservation may mean leaving well alone and simply ensuring that the picture is well protected through conservation framing; in other cases conservation treatment may be essential to protect the picture long-term.

Practices to be avoided as they may significantly reduce the value of the picture are:

The frame

The framing of a work of art may involve making a choice between re-using an existing frame and selecting a new one. Illustration 1 shows a frame package in cross-section with the individual elements of the frame package identified. Whether an old or new frame, the following considerations apply:

Re-using old frames

If an old frame is to be re-used, it should be carefully cleaned and repaired, preserving all inscriptions and framing labels. The frame, mount and glass may be of historical significance. Old decorative mounts such as Victorian gilt mounts can sometimes be re-used with an internal lining. Fixings need to be secured and weakened cord or wire should be replaced.

The conservation mount

The conservation mount comprises a window mount and undermount (sometimes also referred to as a back mount). To provide adequate physical and environmental protection both boards should be at least 1.3 millimetres thick, (4-6 sheet). The boards should be hinged along one edge using either a conservation gummed white paper tape or linen tape, (never pressure sensitive tapes).

The Mount

Because the picture is in direct contact with the mount, the choice of mount board is crucial to protecting framed works of art on paper. As a guide, there are three main categories of mount board and framing.

Museum level
For framing valued original works on paper

Conservation Level
For framing original works on paper

Mounting photographs


Standard level
Not recommended for conservation framing

The hinges


Works on paper need to be mounted clearly away from the glass to allow for air circulation and movement. Pastels and chalk drawings should be held at least 5-6mm from the glass, using either double or triple mounts. If the picture is to be ‘close framed’ (without a window mount) it should be held away from the glass with a small slip, card or fillets (4-6mm deep) tucked under the rebate.  There is a range of glazing materials with different optical properties. Where appropriate historic glass should be reused.

Reducing light exposure

The back board and final assembly

The fittings for hanging