There is no colour concerning which we are more at a loss in looking at old pictures, than the blues. Three are mentioned by Cennino—indigo, a cobalt, and ultramarine. With regard to the sparing use of the latter, as the most expensive, some practical hints may be met with. We have often wondered with what blue their deep-toned cool greens were made, as in the landscapes of Gaspar Poussin. It was probably Cennino's azzuro della magna (German blue or cobalt.) Prussian blue is of recent invention. We believe Mr Field considers it a good colour. It is made of so many hues that it is difficult to procure good, and it is said to be affected by iron. We have heard indigo complained of as a fugitive colour; Cennino mentions it for skies with a tempera of glue. He mentions, likewise, a green cobalt, or azzuro della magna. White lead, according to him, may be used with all temperas. He says it is the only white that can be used in pictures; the whites in the old pictures are very pure, so that we may be satisfied of its durability. Many artists have doubted if the white of the best painters was white lead, and many substitutes have been proposed. We may rest assured, by the authority of Cennino, that the fault is not in the lead, but in the vehicle, whenever it changes. There is a letter of Titian's, in which he laments the death of the maker of his white; it was made, therefore, we are to suppose, with particular care, as the principal pigment for light.
Orpiment, which was so much in use in Sir Joshua's time, the ill effects of which is visible in the President's "Holy Family" in our National Gallery, was no great favourite in the olden time. In the note upon this pigment, the translator takes occasion to speak of powdered glass, in reference to a remark of Dr Ure, that powdered glass is mixed with it, which renders it lighter. Mrs Merrifield infers from this, that it, powdered glass, is opaque. Undoubtedly it is so in its dry state, and probably with the glue tempera, which alone, according to Cennino, is its proper vehicle—but mixed with oil it is transparent—and mixed in much body with pigments, will give them great richness, and that degree of transparency, even to pigments rather opaque, which we observe in the substance of the pigments of the best time. China clay, and magnesia too, are opaque in their powdered and dry state, but mixed with the pigments, vary their power ad libitum, precisely by the transparency they afford. These two latter substances have likewise a corrective quality upon oils, and we are assured by Mr Coathupe, and have certainly found it to be so, that magnesia is a dryer. We have boiled magnesia and oil together, very thick and jelly-like, and leaving the pipkin exposed, have been surprised to find no skin upon the surface. Mrs Merrifield certainly errs in thinking glass, when mixed with oils, opaque. The blacks of Cennino are from a stone, and opaque; from vine tendrils, ("very black and transparent;") from skins of almonds and kernels of peaches, ("a perfect and fine black;") and lamp black, from the smoke of linseed oil. Mr Field observes, that all carbonaceous blacks mixed with white have a preserving influence upon colours, owing chemically to the bleaching power of carbon, and chromatically to the neutralizing and contrasting power of black with white. Leonardo da Vinci in his palette, the account of which is so unfortunately broken off for lack of paper, mentions the mixing every colour with black. Yet we have met with many painters who totally reject it, and fancy it makes their pictures black. This is very absurd, for black mixed with any other pigment ceases to be black; and an artist may paint very black pictures without the use of that pigment. What Titian recommends, one who would be a colourist need not reject. It seems there was of old much caution that iron should not touch the colours. Yet there is, we believe, much iron in ochres. Mr Coathupe has clearly shown, that even Naples yellow does not suffer from contact with iron, otherwise than by abrasion, by which the steel of the knife becomes itself a pigment, as on the hone. Modern science has much enlarged the colour list. There is thus the greater temptation offered to make endless varieties. It has been remarked in language, that the best writers have the most brief vocabulary—so it may be, that the best colourists will have the fewest colours. The rule has been verified in the old masters of the best time. Cennino Cennini, who always begins from the beginning, recommends drawing with the pen—his pen, for that also he tells you how to make, had no slit. O days of Perryian innovation! It was very well, a vast improvement, almost equal to that of adding the shirt to the ruffles, to invent one slit—we have them now with two and with three.
Very strict studies in anatomy were not much in vogue among the early painters. Our author recommends drawing from nature, and lays down his canon of proportions of the human body, which will be little heeded by our academies. The old Italian is not very complimentary to the sex. Mr Etty will open his eyes with alarm, to find he has been practising all his life in a wrong direction, when he reads "leave that of woman, for there are none perfectly proportioned." We are not quite certain, if some of Mr Etty's stay-spoiled figures are taken for examples, but that the opinion of the old Italian may be in some credit. We spoke in the commencement of this paper, of the "Gummi Fornis," which M. Merimée concluded to be copal. The translator, in a note, offers a conjecture, not without its probability, that it may have been sandarac, the "Vernice da Scrivere" of Cennino, and quotes Raffaello Borghini in his "Reposo." If you would have your varnish brilliant, use much sandarac—it makes certainly a very hard varnish—it is difficult to combine it with oil. We suppose it to have been one of the condemned novelties as a vehicle for painting, from its being included in the condemned list of trash, as only fit to polish boots, that moved the satirical pen of Boschini:—
"O de che strazze se fa cavedal!
D'ogio d'avezzo, mastice e sandraca,
E trementina (per no dir triaca)
Robe che ilusterave ogni stival."
Marco Boschini.
Much has been said of late of "Encaustic Painting." It must have been discontinued before the time of Giotto, as shown by the experiments of Lanzi—no wax has been found in pictures painted after the year 1360. We know that Sir Joshua Reynolds frequently used it, as have some painters since his day. We cannot suppose that, mixed with oil, it would ever give pigments their proper hardness.
Dryers are not mentioned by Cennino, excepting verderame (verdigris,) and that as a mordant. How were the oils made to dry? Will the sun be sufficient? In the summers in Italy their mixed oils readily dry. But in Holland, as in England, for at least a great part of the year, they will not dry of themselves; and it is certain that the longer the pigments are subjected to the action of the oil, the greater is the change. White lead is by no means the best drying colour; and if lead, as a dryer, is so injurious as some will have it to be, to colours in general, why do we not find it so in white lead? Cennino recommends garlic pounded to a juice, and cleared, as a mordant. It is supposed that it gives a drying quality to oil. The practice of the old masters in drying their pictures in the sun—was it only to effect the drying? We believe exposure to the atmosphere is most beneficial to newly painted pictures. We have now a picture before us which was disagreeably oily, and yet did not well bear out. We laid it on the grass, face uppermost, where it lay for about ten days during heat and cold, day and night, dry weather and wet, and in some few burning days exposed to the sun; during these hot days, we had it frequently, plentifully washed with water, left on for the sun to take up. We have this day removed the picture to the easel. The "oily appearance" was gone, it was very dry, but pure, and clean, and bore out equally, but rather like distemper. It is a question worth considering, whether the atmosphere did not take up the impurities of the oil, which always come to the surface.
There is proof enough of this. A picture, unless it be painted with very little oil indeed, will become, in a few days after being painted, greasy—it will not take water on the surface—in fact, "secca teme acqua" will not bear water. If, in this state, the surface be lightly rubbed over with common sand and water, this greasiness will be removed, and the surface will not only be clean, but beautiful; this greasiness will, however, in a day or two come again. If the process of sanding be repeated, until the greasiness does not come again, we conjecture that we have done for the picture what time, but a long time, might do—we have removed all the impurity of the oil. We believe that pictures after that do not undergo further change, and if the paint be tolerably hard, may be varnished—and that they will become much sooner hard; for it is more than probable that this greasiness in the oil is the main cause of retarding the drying. We have followed this practice many years, and always with the same results. It is surprising how soon after painting you may sand—even coarse red sand will not remove paint, that is yet tacky—it much remedies the "colori olcesi." The translator lays much stress in the preface upon the importance of white grounds. In the olden time, it appears, that when they were not of gold, they were white; and Leonardo da Vinci thus lays down his precept—"Sempre a quelli colori che vuoi che habino belleza preparerai primo il campo candidissimo, e questo dico de' colori che sono transparenti, perche a quelli che non sono transparenti non giova campo chiaro." And yet Leonardo is said to have painted occasionally on the canvass without any other priming than a coat of glue. His pictures so painted are said to be durable, and worthy his great name. We should have doubted if Titian did always paint on a white ground—and should fix upon the "Peter Martyr" as the subject of doubt. It is said to have been the practice of Correggio; if so, he did not always derive the benefit from the ground which white grounds are said to confer, for his painting is so generally solid, and the transparency so much the effect of his glazing, that there seems to be no reason why he should have given the preference. It is said the Flemish School used white grounds—probably Rubens did so generally, not all other painters. Teniers used a light drab, and, if we were to judge from some of his skies, painted upon it when that thinly coloured ground was wet. Unless a great body of colour be used, even in the most transparent painting, white grounds are apt to give a weakness and flimsiness. Gaspar Poussin, and perhaps generally, Nicolo, painted on red grounds; the former probably often upon a vermilion ground, though most commonly on one of a deeper tone; the advantage of this, in landscapes, such as his, is evident. There is no colour so good as red to set off greens; and in fact, to make tints appear green, that on another ground would not so be; and, moreover, a red ground, from its warmth, makes those greens appear cool, deep, and refreshing, which is so strong a characteristic in the colouring of that great Italian landscape painter, Gaspar Poussin.
The most important recipes of Cennino Cennini may be those which relate to fresco-painting; and as that is now likely to be nationally revived, this publication is well-timed. So much has been said and written of late upon this subject, that we think it best simply to refer to the text and notes. To those who mean to practise fresco, they may be important. Besides the value of the recipes of Cennino, there are incidentally some curious things not unworthy of notice. All persons must have been surprised in pictures of grave subjects, and we might especially mention those of Paul Veronese, that dogs are introduced as attendants on feasts, and we find them gnawing bones on very fine floors. But we find in Cennino Cennini that it was the practice to throw their bones under the table. Cennino recommends them to be gathered and selected for black pigments. We have heard it said that Murillo was partial to the pigments made from beef bones taken after dinner.
There is a practice, or we should say happily there was, in the days of these old painters, which did not tend very much to raise the profession. "Sometimes, in the course of your practice," says Cennino, "you will be obliged to paint flesh, especially faces of men and women." He recommends the painting them with egg tempera, with oil, and with oil and liquid varnish, "which is the most powerful of temperas." He proceeds to tell how the paint is to be removed. Chapter 162 is entirely devoted to the ladies, and offers a caution now happily unnecessary, but it is so quaintly given, that we quote it:—