1. The Renaissance of Rilievo

Baxandall, Michael

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Appendix: Three Notes on Leonardo and Early Renaissance Shadow: 1. The Renaissance of Rilievo

Michael Baxandall

Shadows and Enlightenment

For representing ‘relief’, two main rationales of tonal modelling have commonly been used in European art since the Renaissance, often in combination. One rationale is the tonal representation of the fall of localised light, as in Piazzetta’s instructional engraving (fig. 6), with its imitation of self-shadow, projected shadow and slant/tilt shading. The other is given such names as ‘modelling tone’ (for example, Rawson, 1984, pp. 105–19) and is basically a matter of a tonal range from light to …

Author

Michael Baxandall

PublisherYale University Press

https://doi.org/10.37862/aaeportal.00111.009

Stable URL: https://aaeportal.com/?id=-13763

Chapter subject tags:Leonardo, da Vinci, 1452-1519Relief (Art)Shades and shadows in artDrawingVision--ResearchOptics and art

1. The Renaissance of Rilievo

For representing ‘relief’, two main rationales of tonal modelling have commonly been used in European art since the Renaissance, often in combination. One rationale is the tonal representation of the fall of localised light, as in Piazzetta’s instructional engraving (fig. 6), with its imitation of self-shadow, projected shadow and slant/tilt shading. The other is given such names as ‘modelling tone’ (for example, Rawson, 1984, pp. 105–19) and is basically a matter of a tonal range from light to dark that darkens in proportion to the increase of slant/tilt away from the beholder. A facing surface, perpendicular to the optic axis, is light, and a retreating or receding surface, near-parallel with the optic axis, is dark, reaching maximum darkness at the object’s visible edge or point of self-occlusion from the beholder. A sphere drawn by this method does not have the shadows, shading and highlight of Piazzetta. It is a circle darkening from centre to circumference.

Though drawing or painting with this modelling tone of the second rationale is sometimes referred to as conventional or symbolic, rather than naturalistic in the sense of imitative of phenomena, this is not necessarily true. Of course, it may be taught or may be used by rote or formula. But, to use the terms of §3, even in its purest form modelling tone can be representational of a type of non-Lamhertian and non-specular surface in preponderantly ambient illumination: that is, it can represent reflecting surfaces that do not act as perfect diffusers or perfect reflectors, in conditions where light has been so dispersed by multiple reflection or atmospheric diffusion as to be falling equally from all directions. The surfaces are not like the moon or like a billiard ball, and the light-source is not like direct sun. They are more like someone’s face indoors or on a cloudy day. There is an element of this in most scenes other than a plaster cast or bronze statue lit by a spotlight, and an element of it creeps into all but the most programmatic shadow drawing. It is also extremely important that second-rationale modelling tone can be assimilated to first-rationale phenomenal lighting, if the lighting is posited as from the front.

To the extent that it used tonal differentiation to represent form – and there are other means of graphically or pictorially establishing three-dimensional shape than tonal differentiation – European art was content to use mainly this second rationale for something like a thousand years, from the decline of classical Roman painting to the thirteenth century. The retrieval or re-invention of a first rationale, with shadow and shading from a localised light-source, begins most clearly with the very early Italian Renaissance and this and its circumstances have been fully analysed by Hills (1987), whom I follow for the next paragraphs.

The first crystallization was a synthesis developed by Giotto (fig. 48) around 1300 out of a number of potentialities in the art of the previous century, and adapted to the large fresco narrative cycles he was painting in Florence, Assisi and Padua. Giotto’s synthesis is in some ways an adaptation and enrichment of second-rationale modelling tone. Though there are some exciting experiments with angled and special close sources inside the picture space, a more usual format is to have a light source somewhere between side and front, to offer a clear key to this with boldly lit architecture or little crags, to model the drapery very strongly in general but not dogmatic conformity with it, but almost to play down the side-lighting of faces. For faces Giotto often just turns second-rationale modelling round a few degrees to acknowledge the lighting side, and sometimes up a few degrees to acknowledge the sky. There are certainly exceptions, but a radically shadowed head or anything like a sharp projected shadow is usually a special narrative accent.

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Description: Joachim and the Shepherds by Giotto

Fig. 48 Giotto (d.1337), Joachim and the Shepherds. Fresco, about 200 × 185. Scrovegni Chapel, Padua.

It is important that the light sources are so often and so clearly on our side of the picture plane. This accommodates any second-rationale elements into any first-rationale frame of reference, whether in the painting or in the perceiving; it licenses them (at whatever level of awareness) as more or less consonant with front lighting. Tolerance of the second rationale was one reason why Giotto’s empirical example was so accessible. For a hundred years Italian painters were able to work from it into an astonishing number of local and personal lighting dialects. It ruled nothing out, contained in its details or occasional experiments innumerable suggestions a lesser artist could isolate and specialise into a personal mark, offered resources the most timid artist could adapt to develop this or that old regional idiom. The ‘Giottesque’ school of Florentine fresco painters was only a small part of all this.

The second crystallization, Masaccio (fig. 49) in the 1420s and more particularly the manner in which he was read by the next generation, was quite different, systematic and exclusive. Masaccio had taken elements from the local Florentine ‘Giottesque’ and reduced them to meet the special standards of the new Florentine system of linear, single vanishing-point perspective. Pictorial space was now constructed a priori to a powerful simplified formula, and the lighting was systematized and specialized to interlock with this. The lighting principles learned from his frescoes in the Brancacci chapel (fig. 49) were simple and rigorous: (1) exclude second-rationale tonality; (2) limit variety of object tone, except for special accents; (3) limit the range of object-surface reflectivity, except for special accents; (4) pull the light source right round to the side, only a little in front of and sometimes even behind the picture plane; (5) mark its direction and elevation with selected cast ground-shadows from figures; (6) do shape-from-shading in the middle scale – surface features in the picture plane range 1″–7″ – with a tonal contrast outweighing either projected or self-shadow; (7) in the case of drapery folds, at least, treat self-shadow as transparent through to shape-from-shading.

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Description: Baptism of the Neophytes by Masaccio

Fig. 49 Masaccio (1401–28), Baptism of the Neophytes, about 1424–27. Fresco, 255 × 162. S. Maria del Carmine, Florence.

This is not Masaccio, but Masaccio the functional teacher of coarse rilievo to the Florentine fifteenth century. Masaccio himself had other subtler resources. One of these, the cross-terminator, might be noted representatively. A terminator is the border-line between the illuminated side and the self-shadowed side of an object. Its sharpness depends on the extension of the light source, the reflective quality of surface, and the amount of secondary or global illumination from around: the sun makes a sharp terminator on the Lambertian and isolated quarter-moon. Masaccio often accents his terminators. In figure 49 the mantle of St Peter and the shivering neophyte on the right both exemplify this; the foreground neophyte kneeling in the water does not, being devoted to another resource of Masaccio’s, stretching the three-tone scale. Since the lighting is so much from the side, the terminators register a section of the object running straight into the picture, perpendicular to the picture section. The sections are visible foreshortened (thus stimulating us to conceive depth) on this side of the object and are projected by our stimulated minds for the other invisible side, giving us an armature on which we can conceive it as a rounded volume. Often a sort of quadrature within space is completed by a cast shadow, naturally at right angles to the terminator.

What grew out of the coarse reading of Masaccio over the next fifty years often brutalised Masaccio himself but it became an authoritative idiom which people came to Florence to learn. It effectively killed finer old traditions, like the fluid bracelet modelling of Pisanello; and even when a painter’s view of Masaccio was not coarse, still vulgar Masaccism needed energy to resist. Piero della Francesca, for example, had to resort to an epic journey back to the best of Sienese art of the previous century to arm himself against it. But people learned it because it was teachable, and as a general method, particularly in conjunction with a three-tone scale of values.

The tendency in European art to conceptualize representational tonality in the form of a scale of three tones has been very strong. Usually this takes the same form as the classical scale described by Pliny the Elder (Natural History, xxxv. 29): there is a middle value derived from the object colour, sometimes described as indirectly lit; a dark value derived from the parts in shadow; and a light or high value derived from the illuminated part, which however also has a special super-high occasional accent of lustre included within it. Usually some emphasis is laid on subtlety of transition, harmoge (or joining) to Pliny, but three-tone thinking persists.

It is difficult to know how far this trinity is a product of shaping constraints in the mind and how far of the practical exigencies of mixing pigments in pots, but certainly it was installed in fifteenth-century colour practice and theory (well summarised in, for instance, Gavel, 1979). Writing his discursive recipe-book about 1400 in the Florentine Giottesque tradition Cennino Cennini specified three methods. (1) The basic or general method is a rising scale: hue, hue + white, hue + white + white. This means shadow has the intensest colour. (2) A special, second method, for light-toned pigments only, is: hue + black, hue, hue + white. (Many painters, like Masaccio in much of plate XIII, tended to use mainly the first method for drapery, the second for flesh.) (3) A special, occasional, third method for subtractive secondaries like green is the scale: darker primary (blue), two primaries (blue + yellow = green), lighter primary (yellow). This beautiful method was backed by the broadly classical tradition of hues being a scale of values produced by different proportions of black and white or darkness and light, Aristotle’s version of the scale being: black, blue, green, violet, red, yellow, white.

The three methods Cennini describes survived through the fifteenth century. This gives painting of the period part of its look: a cheerful but irrational chatter between at least three distinct and discrete three-tone colour systems (two of them with preternaturally saturated or colourful shading and self-shadow), in pictures earnestly rational about the consistency of both space and solids, is quattrocento.

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