Changing Impressions - Repairing and lining
by Charles Bestland, after Henry Singleton
published 1802 (1795)
Various repairs are made to rectify physical damage to prints: lost areas are replaced with patches; tears and creases are reinforced; and losses to the printing ink might be touched in. At this stage prints may also be lined, by applying a supporting layer of paper to the reverse.
Bestland's engraving of The Royal Academicians had suffered particularly badly. Sizeable areas at the edges of the paper were lost and it had several vertical creases, caused by the print having been rolled and then crushed flat.
The initial difficulty in replacing lost areas is in matching paper of similar type and weight. Most conservators keep a collection of off-cuts from which they can select suitable pieces for each job .
In selecting paper, style, weight and thickness are of more importance than colour, as paper can be coloured to suit the work in hand.
Among other colourants, cold tea was used in the past. Now this is believed to contain too many impurities and artists' watercolours are the favoured choice. One traditional Japanese infusion which is still in use, however, is of the cones from alder trees. When boiled in water these provide a shade appropriate for many historic engravings, in a form which is easily applied .
The sequence of photographs shows the replacement of the bottom right hand corner of The Royal Academicians. Firstly, the outline of the edge to be matched was pricked onto the replacement paper using a needle . The pricked outline was then followed with a parallel line  so that the paper addition was slightly larger than the area to be replaced. The paper was then torn, rather than cut, along this second line.
In order to allow the patch to overlap the original sheet without standing proud, a scalpel was used to chamfer its edge .
Paste was then applied to the chamfered edge and the patch attached to the print. Having covered the area with protective paper the join was smoothed with a bone tool  and finally weighted and allowed to dry.
The Royal Procession of Queen Elizabeth
by George Vertue
For uneven and complex tears, Japanese paper is more suitable. This is produced from plants, native to Japan, which have a long fibre structure, resulting in a light but strong material. Japanese paper was used to repair the rather uneven tears  in The Procession of Queen Elizabeth.
In order to exploit the fibrous nature of this paper, strips of suitable width are torn rather than cut from the sheet by marking with a mapping pen and water  and then tearing along the resulting weak line  - the fibres can be seen clearly. Paste is then applied to the area to be repaired  and the strip of Japanese paper applied . The resulting repair, after smoothing, is both discreet and strong .
Once the basic physical structure of the print is stabilised, decisions must be made about reconstructing any losses from the design.
On ethical grounds, it is important to respect the integrity of the original artistic work. However, the imperatives of display must also be considered.
As a result of being laid down on stiff board and stored in a drawer with other prints, The Procession of the Knights of the Garter by Richard Cooper had suffered a number of losses to the image.
The area where the two sheets overlap was scuffed and there were 'spot' losses over the entire print. Lumps in the paste used to fix the paper to the board had caused these spots to stand proud and become vulnerable to abrasion .