Part 15

“The next process was to remove the _glaze_ from the saffron robe, composed of yellow lake and burnt sienna. This brought them to a flame colour, in which the _modelling_ had been made. They next attacked the robe of the Virgin Mary, and having taken away the crimson lake, were astonished to find a greenish drab. When they had thus in turn removed every colour in the picture, dissecting every part by diligent care, loosening every glaze by solvents too numerous to mention--including alcohol and various adaptations of alkali--they had the ineffable satisfaction of seeing the _design_ in a condition of crude, blank chiaroscuro. Blinded by enthusiasm, having made careful notes of all they had done, they flew at the white and black with pumice-stone and potash; when, lo and behold! something very rubicund appeared, which further excavation declared was the tip of the red--nose of King George the Fourth! The Titian for which they had sacrificed so much was a false god.”

The foregoing extracts were dictated by the late HENRY MERRITT, a very distinguished restorer and artist, the author of _Pictures and Art separated in the Works of the Old Masters_, and other works of which I can truly say that the name MERRITT indicates that _nomen est omen_. I was often by him while at his work, and had the benefit of seeing the processes employed and the progress which he made in bringing to light the “buried beauties” of pictures by great artists. What I have since learned in addition will be found in the following pages.

Though it is simple and easy to describe the manner in which old pictures in general are restored, it must be borne in mind that, as regards a detailed and comprehensive description, the task would be the most difficult in the whole range of repairing; for when a picture has suffered so much that repainting is absolutely necessary, then nothing but the skill of the original artist himself would ever do full justice to it. In many cases we have pictures, like decayed works in wood, so far gone that only a mere hint or sketch of the original remains, so that they are generally deemed not worth keeping. In such cases the restorer or repairer may very well do his best. There is, and always will be, an immense field for every skilled repairer in this remaking of antiques, to great profit, because there is an unlimited supply of material, almost everywhere, wherewith to work.

To be a perfectly accomplished restorer of pictures one should be an expert in chemistry, and not only one very familiar with all the styles and schools of art, and gifted with great knowledge of the _technique_ of great artists, but also no mean painter oneself. There is a very general, but very vulgar and stupid, popular belief that the restoration and cleaning of old pictures is a merely mechanical art, about on a par with house-painting as regards skill or intelligence; but this I earnestly deny, having found, since I have practised it myself, that it affords a wide field to ingenuity, and that the greatest artists living--I care not who they may be--can find in restoration tasks which would fully tax all their skill, knowledge, or genius.

Before proceeding to clean or repair a picture it is often advisable for the artist to make an outline sketch of it with great care, in order to correct and guide him in details. To do this, take very transparent tracing-paper--the recipe for making which is elsewhere given--then with a soft crayon-pencil, or a very black lead-pencil (from 3 to 4 B), trace the whole. If the paper be not transparent enough, then use thin glass, or, what is far better, sheets of mica, gummed together at the edges, which will not break even if dropped. Trace the picture on this with a fine brush and black oil-colour, or any black paint which will hold. Then make a tracing from this on transparent paper. To transfer crayon or lead pencil drawing to wood or paper, very slightly dampen the surface of the latter, lay the tracing on it face down, and rub the back of the latter with a burnisher or ivory paper-knife. It will thus be perfectly transferred. This making preparatory sketches or copies will be found in many cases extremely useful, as training the eye carefully to the work to be done.

It is not _invariably_ true, though a great authority on picture-cleaning (HENRY MOGFORD) has declared the contrary--that “pictures ... unquestionably enjoy their highest perfection at the first moment of production.” Many artists recognise the truth that a year, or even years, are needed to give a certain delicate tone, which is like the ripeness of fruit, to certain pictures; and the same is true of certain artists, though by no means in the same degree of all. But there are many persons who can associate the mellowing tones of age or the venerable grey of antiquity with nothing but dirt, decay, and poverty; as was the case with an Italian marquis, who, having heard that a distinguished artist[4] had copied an old moss-grown wall or fragment of ruin on his estate, sent an apology to the latter, stating that if he had known that such a distinguished person intended to copy it he would have had it cleaned and lime-washed, not in glaring white (he knew better than that, he said), but in light blue! So I have known an American gentleman to be distressed at discovering the appearance of lichen on a corner of a “spick-and-span, brand-new villa,” which he at once declared must be cleaned and painted all over. People who suffer from this vulgar mania of over-scouring are apt to imagine that when they detect the least sign of age in a picture it suggests dirt and neglect, and hurry it off to the cleaner; unless, indeed (as is too often the case), they--with insufficient knowledge, and with “notions generally derived from guess-work, and suggested by the usual arrangements for taking care of other household objects”--attempt to restore the work themselves, which has been the cause of the ruin of thousands of great works of art.

It may here be observed that modern pictures, owing to the hurried processes of manufacture and the use of cheap materials in machinery-made paints, change so rapidly that many lose half their value in fifty years’ time. And, as if this were not enough, we have the sulphuric acids generated by coal-fires (especially that from anthracite coal in America, which even eats away the lime in chimneys), as well as the deleterious effects of gas, vapours from food, and, finally, the want of air and light in ever-curtained and shaded rooms.

The causes, in fact, which lead to deterioration in pictures are almost as many as those which produce diseases in man, and in not a few instances they will be found to be the same. These are, as I have said, foul air or malaria, or want of fresh air, dampness, the smoke of candles in churches, too long exposure to sunshine, the exhalations of charcoal, sulphur, sinks, &c.; “in short, all penetrating scents are injurious to painting, especially if it be new.” Owing to this prevalence of gas and coal smoke in houses, allied to the bad quality of paints, as now manufactured cheaply by machinery, it is, indeed, considered doubtful whether any of the pictures painted during the reign of Queen Victoria will exist in “half-visible” condition fifty or a hundred years hence. There is, as regards them, a grand future for the restorer. One need only look at most of Turner’s earlier pictures to fully verify what is here asserted.

The face of all old pictures long untouched will always be found covered more or less with what is simply dirt; that is, dust more or less dissolved by moisture. Now, dust consists simply of all kinds of substances, even invisible extinct animal organisms in vast numbers. The first step is simply to wash away this dirt with distilled or rain water and ox-gall. Use a very soft, clean sponge, and pass it over the picture many times. The last time wrap the sponge in a clean, white linen or muslin handkerchief to see whether the surface is quite clean. This and nothing more will often produce an astonishing improvement.

The next task will be to remove the varnish. _Hot_ water attacks any varnish, reducing it to a dry powder; but, as M. GOUPIL remarks, this is _très hasarde_, or is very risky, because it may also attack and dissolve anything like gum or glue in the colours. M. GOUPIL, however, sanctions the use of cold water in cleaning even to mere abuse, in which he is in contradiction to HENRY MOGFORD, whose work I regard as by far the best with which I am acquainted on the subject of cleaning and restoring pictures which I have read.[5] On this subject he says:--

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“During all operations of lining, and of picture-cleaning generally, saturation by water is attended with disastrous effects, and the use of it should therefore be limited to application by means of a squeezed piece of sponge, or, what is better, a piece of buff leather, soaked and wrung out. Water is a most dangerous enemy to pictures; it penetrates to the priming or ground, loosens them by promoting decomposition of the size with which they are worked, and thus lays the foundation for their eventual disintegration and decay. Imbibed damp will sooner or later cause the destruction of every woven material, and while our daily experience shows its lamentable effects on the walls of our dwellings, it will be well for us to remember that it is no less destructive to the canvas of our pictures, and to the materials which form its priming.

“All the pictures of the early masters of the Italian school, and those of Claude and William Vandervelde, which are painted on chalk and absorbent grounds, are in the greatest danger if washed with water. It penetrates through the small crevices which may exist in the paint, and often totally destroys the picture. If the painting be upon canvas, like those of the two latter-named masters, it breaks into a thousand small lines or cracks; and if upon panel, like the pictures of Raffaelle, Andrea del Sarto, or Fra Bartolomeo, it breaks up the paint by scaling it off in small points of the size of a pin’s head. If the picture, again, is of the Spanish school, and is painted upon the red absorbent grounds and upon a rough canvas, water not only breaks the unity of its surface, but from the canvas being of a coarser texture than the pictures of Claude or William Vandervelde, it often penetrates in a greater proportion, and frequently scales off pieces as large as a sixpence, especially in the dark shadows, or where the ground has not been sufficiently protected by a thick _impasto_ (heavy coat or ground) of colour. At all times and to all pictures water is more or less dangerous, unless used with the greatest caution, and then it should only be applied by means of a piece of thick buckskin leather well wrung out, and left just wet enough to slip lightly over the surface of the picture. In the case of some masters, as with those we have specialised above, the free use of water may be regarded as next door to absolute destruction; and the warmer and drier the weather the more active and ruinous the operation. Instances have occurred in which an Andrea del Sarto, a Claude and a William Vandervelde, were destroyed in a few minutes by the injudicious use of simple water.”

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I have given this quotation in full, because water is generally the first thing freely resorted to clean pictures by the ignorant. Thus I have heard of very valuable pictures being actually given to common servants or the washerwoman to scour clean, which was effected with soap and hot water and sand, to the speedy ruin of the work. Nor is it any great wonder that this should be done, when we find in GOUPIL’S work that, while he admits that cold water “infiltrates itself partially to the fissures of a painting and does great harm,” he declares that “_hot_ water acts differently,” giving the impression that it may be very freely used, and declaring that “clean cold water harmlessly dissolves grease and dirt resulting from dust deposited by the air.” This is true, but he does not seem, like Mr. MOGFORD, to have fully understood the other side of the question. (_Manuel Général et Complet de la Peinture à l’Huile_, par F. GOUPIL.)

For first cleaning away impurities from a surface MOGFORD recommends _ox-gall_ to be applied with a soft brush. This may be obtained in shilling or six-penny bottles from Winsor & Newton, or any other dealers in artists’ materials. “It is,” he adds, “an excellent detergent, which may be freely applied without fear. It must, however, be well washed” (_i.e._, wiped) “off with pure water, or it will leave a clamminess on the surface that may prevent the varnish, afterwards applied, from drying.” But a distinction must be carefully borne in mind between _washing_ with water and letting it _soak_ into a picture and simply wiping off the surface with a damp chamois or buckskin or soft _old_ linen handkerchief. In fact, this latter is the first thing to be done before slightly cleaning the surface with the diluted ox-gall. It is very necessary that the skilled cleaner shall understand exactly the nature of varnishes, so as to know on what he is to work. Thus, according to the picture, he may employ “liquor potassæ, oil of tartar, spirits of wine, pure alcohol, liquor ammoniæ fortis, naphtha, ether, soda, and oil of spike or lavender. The very nomenclature of these powerful agents will at once show the great risk of their being injudiciously or carelessly employed.”

Great care should be taken not to allow an excessive or unequal quantity of cleaning fluid to gather in one place. Therefore all pictures should be laid flat while being restored, as streams, for instance of ammonia, would cut very irregularly into a surface. With pictures of any value, the process of cleaning is always very delicate, requiring much practice and very perfect knowledge of all the principles of the art.

Where the varnishes are tender and thin, such as mastic, MOGFORD advises the use of spirits of wine; but to be sure that no harm can be done by it, it is desirable that “the spirit, which is usually sold at 58° of strength, should be diluted by a fourth part of water, or by the same proportion of rectified spirits of turpentine, or it may be used with an addition of a sixth part of linseed oil, added to the diluted or pure spirit.” In every instance the mixture is to be “well shaken before taken,” or applied. Care should be taken to prevent oil from softening the paint, which it is apt to do. As a rule it is best to begin with the lightest or brightest portions of a picture--as, for instance, the face of a portrait--as these parts are always the hardest. Beginning by wiping the surface with white cotton wool and turpentine, observe if any varnish comes off on it, and as soon as it is seen change the part of the rubber used, else you will go on simply taking up “dirt” from one place and rubbing it into another. This is elsewhere explained as regards cleaning cloth or absorbing ink, that we must continually subtract from and not add again to the ground.

“Turpentine is a counteracting medium, which instantly arrests the action of the solvent spirit.” When all the varnish has thus been removed, the whole may be wiped over with spirits of turpentine, and then when dry revarnished, if nothing more be required.

Rubbing with the fingers, or powders, or any kind of dry cleaning must be avoided, or else practised with great care, since it produces an effect known as _woolliness_, which will begin to show very decidedly after some time. But when a picture has had no varnish it can only be cleaned mechanically, as by using tripoli, pumice-stone, or whiting. This method requires great skill. Sometimes a very fine-edged scraper or knife is used to thin the varnish before using turpentine.

“Solvents,” adds Mogford, “are only necessary to remove _varnish_.” Unvarnished pictures are best cleaned by carefully wiping with buff or chamois leather, damp, not _wet_, aided by a little powdered whiting.

Varnish, when not on a picture, may, however, be removed by rubbing it with the fingers, or palm, or leather, aided by powdered resin, or rosin. For certain purposes, as to make a panel of a piano thoroughly seasoned for heat, and, as it were, enamel it, a coat of varnish is applied, and when dry is rubbed down smooth with pumice-powder or resin, and this process is repeated many times.

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.

Wood-ashes, _very_ finely sifted, are spread on the face of the picture, and delicately, or carefully and lightly, rubbed with a soft sponge. This must be carefully washed away as soon as the surface is cleaned.

Other detergents failing, borax dissolved in water may be employed. This works slowly but surely; but, as M. GOUPIL remarks, this _lessive_, like wood ashes, must not be left long on the colours, but be promptly wiped away with a sponge. Lime-water will serve as well as the solution of borax.

Soaps of different qualities are also used for cleaning, according to the state of the picture. It may be here again remarked that no exact rule can be given regarding an art specially founded on skill and experience. The beginner should first try his hand on a few common old pictures.

Soap made into a foam or lather with water will generally clean a surface, however dark it may be from smoke. Let the foam settle completely, and then wipe it clean with a damp sponge.

Essential oils, especially turpentine, or those of spikenard, lavender, and rosemary--of either two parts of spirits of wine to one of turpentine, &c.--are commonly used to clean pictures.

Pictures not varnished require great care and skill in cleaning. For these _yeast_ with water, or flour mixed with lime-water, is employed; also spirits of wine or vinegar. Ammonia is also used. GOUPIL mentions that one of the most dangerous mediums for this purpose is the old one of urine, and that it should never be used.

When the canvas of a picture is very old and rotten, it may be replaced by a process requiring the utmost nicety. If only certain portions are injured, it will suffice to glue pieces of fine canvas on the back.