A Manual of Mending and Repairing; With Diagrams

by Charles Godfrey Leland

If pictures are painted in oil, directly on canvas, without a ground, the paint sinks down in between the threads and lies thinly on them. Therefore if there is rubbing on the surface the grain of the canvas becomes very apparent. If oil-paint be laid directly on a panel of wood, the soft parts between the hard fibres, lines, or grain shrink away, drawing the paint with them. Old artists avoided this by laying on a strong ground of gesso or plaster of Paris mixed with glue or white of eggs.

The great task in cleaning is to remove the repainting or coats of paint which have been added by restorers. I have seen this done with extraordinary skill by the late Mr. Merritt, who was recommended by Ruskin, and who was the first and most truly artistic restorer of his time. I can recall his cleaning the most beautiful Carpoccio which I ever saw, and a magnificent Velasquez, both of which had been repainted again and again, and were in such wretched condition that even the painter of the latter had been mistaken. They bore about the same relation when untouched and afterwards that a dirty old rag has to a magnificent cashmere shawl. “Caustic, soap-makers’ lye, liquor potassæ, pure alcohol, and the scraper,” remarks Mogford, “are the ordinary means to take off repaints; all of them dangerous appliances if not closely watched and used without violence or carelessness.”

It is advisable to examine carefully the backs of old pictures for signatures, date, or documents, all of which are sometimes pasted over with other paper or canvas. Once, in Florence, I found in a small shop a portrait of Charles I., but differing in many respects from any which I had ever seen. I told the owner that it was by Vandyke, but he insisted on it that it was by an Italian with some such name as Guillermo or Gillonio, till I proposed that we should examine the back, where we found, after some investigation, the name of Vandyke. At which discovery the dealer promptly raised the price of the picture from one hundred to one thousand francs, and it was, indeed, cheap enough at that. A lady to whom I narrated the occurrence said, “Oh, why didn’t you buy the picture before you told the man who painted it?” To which I replied, “For the same reason that I did not steal a valuable ring out of the case in the shop when his back was turned.” Much is said about the shrewdness of dealers in antiques, but it has often happened to me to explain to them that articles in their possession were worth far more than they imagined; while, on the other hand, they will, surmising that a thing may be worth a great deal, charge a fearful sum for something that is merely cinque cento; e.g., a thousand francs for what is really dear at ten. I mention this in order that the reader may realise (which few do) what bargains may be picked up by any one who knows anything of art, and especially of the humble art of cleaning, mending, or restoring, which lets us into a world of secrets even in high art, and which is of more use to a picture-buyer than all the high-flown æsthetic culture in all the works of all the rhapsodists of the age.

The preceding remarks on cleaning were drawn chiefly from the manual by H. Mogford, and my own experiences. I add to them those of M. Goupil on the same subject. The intelligent leader will find no difficulty in collecting and drawing his own inferences from both:—

“When the picture is certainly in oil, steam may be used to remove the varnish. There is, however, the great risk of loosening the painting from its ground.”

But when a picture has been, instead of varnished, glazed with white of egg, we have a coating which, when old, cannot be dissolved by water or acids; for this other and specially elaborate detergents, or cleaners, are employed. There are few substances which so persistently harden with time as the white of egg, as does also the yolk when boiled.

Ordinary varnish, when dry and old, can be removed by mechanically scraping or rubbing with fine, dry powders, such as that of resin. The dust from the varnish itself aids in the operation. This process is slow and tiresome, but it is very often advisable to begin with it, after washing, as it does not injure the colours. It is needless to say that it requires great skill, care, and experience not to “cut into the colour.”

It may be remarked, as regards this, that in all cases where there is a difference of opinion between the French and English artist—as in the use of water—we must remember that both are, or may be, in the right as regards certain kinds of pictures. So varied are the methods of painters that it seems to me to be by far wiser to describe different methods than to attempt the impossible task of giving infallible rules.

“Varnish can be removed by means of spirits. To effect this, lay the picture on a table, and wet a small portion of it with spirits of wine. After a minute or more, wash the place with clean water and a sponge. Thus, little by little, clean the entire surface, taking care not to injure the paint, When quite dry, apply new varnish.”

Practised restorers, who can tell by examination and knowledge of the methods employed by painters what they can venture on, often use detergents which would ruin the picture if applied by a person without experience. These are alkaline salts, such as wood-ashes or lye, pearl and pot ashes, or salts of tartar, all of which, except the latter, are extremely hazardous for a tyro. Salts of tartar may be safely employed if we begin with a feeble solution, which may be gradually strengthened.