Leonardo da Vinci

by Sir Kenneth M. Clark

  It was in order to establish scientifically the determinable boundaries of shadows on curved surfaces that he drew the long series of diagrams showing the effect of light falling on spheres and cylinders, crossing, reflecting, intersecting with endless variety, which we find in MS. C of about 1490. The calculations are so complex and abstruse that we feel in them, almost for the first time, Leonardo’s tendency to pursue research for its own sake, rather than as an aid to his art. How far, in fact, his art was affected we cannot determine. The drawings which show his greatest mastery of chiaroscuro from a naturalistic point of view belong to the years just before this period. He never surpassed the rendering of light passing over curved surfaces in the studies of skulls dated 1489. But it is characteristic of his development that he should grow dissatisfied with this empirical mastery and wish to reduce it to rule. Critics have complained that the scientific study of light and shade led to a kind of academism in Leonardo’s later work, and was ultimately responsible for the artificiality of the Louvre St. John. This is certainly untrue. Much of Leonardo’s most sensitive and unacademic use of chiaroscuro dates from long after his investigations into its nature. And to those who maintain that the innumerable patient diagrams of criss-cross rays were a tragic waste of time, Leonardo might well have replied that between the Ginevra Benci and the Mona Lisa there is a difference in fullness and continuity of modelling which he, at any rate, could only have achieved by the scientific study of light striking a sphere.

  The effect of Leonardo’s passion for chiaroscuro, both in his own art and in that of his followers, I shall discuss later on. But while dealing with the Trattato I must quote one passage which has a bearing on his whole feeling for the subject. ‘Very great charm of shadow and light,’ he says, ‘is to be found in the faces of those who sit in the doors of dark houses. The eye of the spectator sees that part of the face which is in shadow lost in the darkness of the house, and that part of the face which is lit draws its brilliancy from the splendour of the sky. From this intensification of light and shade the face gains greatly in relief...and in beauty.’{37} Here is the description of a seicento picture, a Caravaggio or a Rembrandt, as far as possible from the theory and practice of Leonardo’s day, or, as we shall see, his own academic theory.

  Next to perspective the branch of science which played the greatest part in the traditional discipline of the Florentine school was anatomy. To Castagno it had seemed to offer the basis of scientific realism, to Pollajuolo the mastery of movement. With proportion it lay at the root of Renaissance aesthetics, for if man was the measure of all things, physically perfect man was surely the measure of all beauty, and his proportions must in some way be reducible to mathematical terms and correspond with those abstract perfections, the square, the circle and the golden section. It is not surprising, therefore, that Leonardo studied anatomy with passion throughout his life, and applied his knowledge in painting the great composition of the Battle of Anghiari, and in preparing the lost treatise on the human figure referred to by Pacioli. But quite early his intellectual curiosity led him to investigate aspects of anatomy which could not conceivably benefit his painting. The anatomical drawings in the Windsor MS. B, dated 1489, are studies of skulls, done with a delicacy which makes them works of art, but with scientific intention (Pl. 28). This intention is made even clearer in some drawings, done perhaps a year or two later, showing the structure of a bear’s foot. Quite recently three drawings by Leonardo have been discovered representing the actual bear. Leonardo had drawn its paws while alive; on its death he dissected it in order to compare them to the human foot. This idea of comparative anatomy appears again in his drawings—he compares the arms of men and monkeys,{38} the legs of men and horses{39}—and is typical of the workings of his mind. It springs from his conception of man as a part of nature, subject to the same laws of growth, controlled by the same chemistry; a conception which transcended his scientific researches, and is one of the roots of his art.

  The third branch of the art of painting on which Leonardo insists is proper treatment of the subject. It must be natural, circumstantial, and dramatic. He is continually advising the painter to study appropriate gestures and expressions. The student is warned against monotonous attitudes, and in particular against the danger of reproducing his own physical characteristics,{40} a danger more real than might be supposed. Of dramatic impropriety he gives an amusing example: ‘I recently saw an Annunciation in which the Angel looked as if he wished to chase Our Lady out of her room with movement of such violence that she might have been a hated enemy. And Our Lady seemed as if in despair she was about to throw herself out of the window. Remember not to make such a mistake as this.’{41} We may speculate with interest on the author of this picture seen a questi giorni, a probable answer being Botticelli, who in the enthusiasm of his later work was carried beyond classical decorum. This aspect of Leonardo’s teaching is easily remembered in front of the Last Supper, and we shall have reason to refer to it again. But we must also keep it in mind when we come to look at those of his compositions in which the treatment of the subject is less obvious, in the St. Anne, in the Leda, and, above all, in the St. John. Strange and perverse as his presentations of these themes may seem, we cannot, with the Trattato before us, dismiss them as merely capricious.

  In addition to defining the principal aims of painting, Leonardo gives us practical hints as to how they can be achieved, interesting to us as indications of his own studio practice. He tells the student to avoid above all light which casts a dark shadow, so that even if he is painting in the open air he must do so as if some mist or transparent cloud was between his object and the sun.{42} In sunlight it is better to paint in a courtyard with high walls painted black and a linen curtain stretched over it. The ideal light falls on the object at an angle of 45 degrees. This last shows Leonardo at his most academic, and is a contrast to the Rembrandtesque figure looking out of a dark interior, described above. More sympathetic are his numerous instructions as to how to catch that degree of animation in figures which he valued so highly. ‘When you are out for a walk,’ he tells the painter,{43} ‘see to it that you watch and consider men’s postures and actions as they talk, argue, laugh, or scuffle together: their own actions, and those of their supporters and onlookers: and make a note of these with a few strokes in your little book which you must always carry with you. This book should be of tinted paper so that you cannot rub out, but always go on to a new page.’ He also gives the very sound advice that any student drawing a detail of a figure should first sketch in the figure as a whole, so that the real meaning of the finished part should not be lost sight of. Good examples of his own practice are the studies of the nude at Windsor. These practical hints show how far he was in revolt against the decorative style of the quattrocento. Painters are warned not to surround their figures with dark outlines;{44} rows of frescoes one above the other, the time-honoured Italian way of telling a story in pictures, is blamed on grounds of reason (ragionevolmente biasimato), and as an alternative Leonardo suggests putting several scenes in the same composition, but cutting them off from one another by ‘large trees, or angels if they are suitable to the story, or birds or clouds or similar devices’.{45} Scorn is reserved for mere decorators. ‘There is a certain race of painters,’ he says, ‘who from their lack of science have to live by the beauty of blue and gold—vivano sotto la bellezza dell’oro e dell’azzuro. With supreme folly these men allege that they cannot do anything good except at a high cost.’ I think there can be little doubt that Leonardo was actually thinking of Pintoricchio, who was notoriously extravagant—Consuma, said the papal secretary of him, troppo vino, troppo oro e troppo azzuro. In any case, these maxims foreshadow that great stride in the history of art which the visitor to the Vatican can take by climbing the stairs from Pintoricchio’s Borgia Apartments to Raphael’s Stanze.

  Interesting as are the theories and precepts propounded in the Trattato, and important in their bearing on Leonardo’s painting, it cont
ains entries of a far deeper significance. These are the passages in which he reveals his own preferences, prejudices, and the real colour of his imagination. His manuscripts, for all their enormous bulk, so seldom contain the least expression of personal feeling that the passages preserved by the unknown editor of the Trattato are worth examining at length. In the first place, Leonardo makes fairly frequent reference to the sort of subject the painter might wish to treat. Here is one of them, the 65th chapter of the Trattato, headed ‘Piacere del Pittore’.

  The painter can call into being the essences of animals of all kinds, of plants, fruits, landscapes, rolling plains, crumbling mountains, fearful and terrible places which strike terror into the spectator; and again pleasant places, sweet and delightful with meadows of many-coloured flowers bent by the gentle motion of the wind which turns back to look at them as it floats on; and then rivers falling from high mountains with the force of great floods, ruins which drive down with them uprooted plants mixed with rocks, roots, earth, and foam and wash away to its ruin all that comes in their path; and then the stormy sea, striving and wrestling with the winds which fight against it, raising itself up in superb waves which fall in ruins as the wind strikes at their roots.

  The rest of the passage is a description of the struggle between wind and water, in which the water takes the form of rain to assault the sea from above, but finally ‘pressed back it turns into thick clouds, and these become the prey of the conquering winds’. Here is Leonardo carried away by his true feelings. He begins to enumerate the subjects that delight a painter, and instead of compositions of figures, classical and religious legends, beautiful faces and draperies, all the subjects which pleased the patrons and artists of his time, he describes this combat of the elements, a subject for Turner, in the language of Herman Melville. Nor was this an isolated freak. All his longest and fullest descriptions of pictorial subjects are of great battles, storms, and deluges{46} and, as we shall see, he carried out these subjects in the most personal of all his designs (see p. 151). Unfortunately, we have no hint of how he would have executed another subject, which he describes with equal pleasure, a night piece with a fire,{47} and when we try to picture it our eye cannot rid itself of the strong images created by an artist at the farthest remove from Leonardo, the night pieces of Rembrandt.

  The figures which are seen against the fire look dark in the glare of the firelight; and those who stand at the side are half dark and half red, while those who are visible beyond the edges of the flames will be feebly lighted by the ruddy glow against a black background. As to their gestures, make those which are near it screen themselves with their hands and cloaks, to ward off the intense heat, and some with their faces turned away as if drawing back. Of those further off, represent some of them with their hands raised to screen their eyes, hurt by the intolerable splendour of the flames.

  These descriptions not only show the deeply romantic colour of Leonardo’s imagination: they imply a sense of form completely at variance with that of his contemporaries. Instead of the firmly defined forms of the quattrocento or the enclosed forms of the high Renaissance, the subjects he describes could only be treated with the broken, suggestive forms of romantic painting. That Leonardo felt the full evocative power of such forms is proved by a famous passage in the Trattato:{48}

  I shall not refrain (he says) from including among these precepts a new and speculative idea, which although it may seem trivial and almost laughable, is none the less of great value in quickening the spirit of invention. It is this: that you should look at certain walls stained with damp or at stones of uneven colour. If you have to invent some setting you will be able to see in these the likeness of divine landscapes, adorned with mountains, ruins, rocks, woods, great plains, hills, and valleys in great variety; and then again you will see there battles and strange figures in violent action, expression of faces, and clothes, and an infinity of things which you will be able to reduce to their complete and proper forms. In such walls the same thing happens as in the sound of bells, in whose strokes you may find every named word which you can imagine.

  Later he repeats this suggestion in slightly different form, advising the painter to study not only marks on walls, but also ‘the embers of the fire, or clouds, or mud, or other similar objects from which you will find most admirable ideas...because from a confusion of shapes the spirit is quickened to new inventions.’ ‘But,’ he adds, ‘first be sure you know all the members of all the things you wish to depict, both the members of animals and the members of landscapes, that is to say, rocks, plants and so forth.’

  I have quoted this passage at length, familiar as it is, because it is profoundly characteristic of Leonardo. Nothing could be farther from the precepts of academic classicism than the use of stains in walls as a stimulus to the imagination. This procedure was followed by Goya, one of the most anti-classical of all painters; and Victor Hugo, whose name is the first to come to mind when we read Leonardo’s descriptions of a deluge, made many of his strangely exciting drawings out of accidental blots and smears of coffee. Yet although Leonardo would admit such aids to the imagination, his conception of art as a science forced him to add a warning that the painter must understand the detailed structure of all that he wished to represent.

  Before leaving the Trattato I will take the opportunity of quoting from it a few of the passages which throw some light on Leonardo’s character apart from his ideas on painting. First of all, we have some firsthand confirmation of those early authorities who tell us that he was elegant, solitary, and calmly aware of his superiority to the average of mankind. This is apparent in his perfectly illogical attacks on sculpture. Sculpture, he says, is not a science, but an arte meccanicissima, for

  the sculptor in creating his work does so by the strength of his arm by which he consumes the marble, or other obdurate material in which his subject is enclosed: and this is done by most mechanical exercise, often accompanied by great sweat which mixes with the marble dust and forms a kind of mud daubed all over his face. The marble dust flours him all over so that he looks like a baker; his back is covered with a snowstorm of chips, and his house is made filthy by the flakes and dust of stone. The exact reverse is true of the painter (taking the best painters and sculptors as standards of comparison); for the painter sits before his work, perfectly at his ease and well dressed, and moves a very light brush dipped in delicate colour; and he adorns himself with whatever clothes he pleases. His house is clean and filled with charming pictures; and often he is accompanied by music or by the reading of various and beautiful works which, since they are not mixed with the sound of the hammer or other noises, are heard with the greatest pleasure.{49}

  We are reminded of the description by Jusepe Martinez of El Greco in a great house with twenty-four rooms and a band of musicians to play to him while he took his meals. But with Leonardo (as, indeed, with El Greco) this elegant way of life was combined with great austerity. ‘In order that the prosperity of the body,’ he says, ‘shall not harm that of the spirit the painter must be solitary, especially when he is intent on those speculations and considerations, which if they are kept continually before the eyes give the memory the opportunity of mastering them. For if you are alone you are completely yourself but if you are accompanied by a single companion you are only half yourself.’{50} And we know that Leonardo showed that perfect contempt for riches which he counsels so eloquently in chapter 62 of the Trattato.

  Leonardo’s description of the sculptor has a further significance for us. It is an unmistakable reference to his hated rival, Michelangelo. The very hardships which Leonardo describes in derision are recorded with a kind of sardonic pride in Michelangelo’s letters and sonnets. We see that the antipathy, the sdegno grandissimo as Vasari calls it, which existed between the two men was something far more profound than professional jealousy; sprang, in fact, from their deepest beliefs. In no accepted sense can Leonardo be called a Christian. He was not even a religious-minded man. It is true that he allow
ed himself an occasional reference to superstitious observances: thus he writes ‘of Worshipping the pictures of Saints. Men will speak to men who hear not....They will implore favours of those who have ears and hear not; they will make light for the blind.’ Here and in a few other passages he seems to associate himself with the precursors of the Re-formation. But these protests spring from his dislike of mumbo jumbo and loose thinking in general rather than from any real religious conviction. Michelangelo, on the other hand, was a profoundly religious man, to whom the reform of the Roman Church came to be a matter of passionate concern. His mind was dominated by ideas—good and evil, suffering, purification, unity with God, peace of mind—which to Leonardo seemed meaningless abstractions, but to Michelangelo were ultimate truths. No wonder that these ideas, embodied in a man of Michelangelo’s moral, intellectual, and artistic power, gave Leonardo a feeling of uneasiness thinly coated with contempt. Yet Leonardo held one belief, implicit in his writings, and occasionally expressed with a real nobility: the belief in experience. Such an expression is to be found in chapter 29 of the Trattato, in which Leonardo denies with passion the old scholastic belief that only those sciences which have their origin in abstract intellectual speculation can escape the charge of being ‘mechanical’.