Restoration and Preserva Tion of Paintings

It will be seen from the above what the vulnerable points of a picture are. At the same time it will be shown that it is rare for one element only to be affected; when one of the elements which constitute the picture is injured, the effects generally make them selves felt on the remaining elements.

Damp and heat are the chief natural destructive agents. In addition there is the possibility of splitting in the case of a wood panel, and tearing in the case of canvas, owing to violent treatment.

Injuries to the supporting structure may be repaired by cradling in the case of paintings on wood panels, by re-lining in the case of pictures painted on canvas, and by transference in the case of either kind of picture. The same processes can be applied to pic tures painted on paper. Pictures are also occasionally painted on slate, copper or other metals ; in such cases there is very little possibility of repairing any damage to the supporting structure, since the coating of paint which constitutes the picture can only be refixed from the front.

Cradling.

When a picture painted on a wood panel splits owing to rough treatment or changes of temperature, it becomes necessary to join up the pieces which have become separated and to restore an absolutely flat surface to the panel. In order to do this, the pieces are fitted together carefully and are laid, with the painted side downward, on a sheet of marble or glass. They are then subjected to heavy but grad ual pressure so that the straight ening out of the wood may not be too sudden. If the panel is a thick one, it is better to shave it away so that it may be straightened more easily without there being a danger of its split ting again. It is also a good thing to make the surface of the re verse of the picture perfectly flat so that the cradling may be car ried out more satisfactorily. If the panel is very badly damaged it may be backed with another; the actual cradling is then carried out on the second panel. Cradling consists in gluing a series of small pieces of wood at small and regular intervals over the whole surface of the reverse of the picture. The wood selected must obviously be perfectly dry; and in order to prevent any fresh damage due to changes of temperature, care is taken not to glue the pieces of wood to one another at the points of intersection.

Re-lining.--The

tearing of the canvas of a picture by a fall or some other accident always impresses the general public as a particularly serious disaster. The injury may in fact be serious if the vital parts of the picture are affected, but it may be compara tively slight if only the less important parts are damaged. If the canvas on which the injured picture is painted is in good condi tion, the process of re-lining is applied; in other words, the dam aged fabric is reinforced by the process described on next page.

The painted side of the damaged canvas is first covered with a sheet of paper for protection, and the reverse side is then carefully cleaned and covered with two coats of fish-glue. It is then covered with gauze applied by means of a special kind of glue made of a mixture of rye flour and wheat flour, fish glue and a little Venetian turpentine or molasses. The new canvas, which must be of pure linen and carefully sponged, is then stretched on a temporary frame larger than the picture to be re-lined. These preparations having been com pleted, the new canvas and the reverse of the old canvas are glued together by means of the special glue described above ; when the two canvases are placed one against the other; any in equalities in the thickness of the glue are pressed out with a spa tula. The re-lined canvas is then ironed several times; this is of great importance in order to make the junction between the two can vases complete. When the junc tion is effected and the glue has completely dried, the protective covering of paper is removed from the picture and the re-lined canvas is stretched on its perma nent stretcher. Any gaps in the painting made by the tear are filled in with a mastic made of carbonate of lime, fish glue and a little Lyons glue. It need hardly be said that this is only an outline of the process of re-lining, and similarly, only an outline of the process of transference will be given ; it will be readily understood that these operations require the most detailed attention, and that proper time for drying must be allowed between the different stages.