Sculptors are accustomed, in working their marble statues, to begin by roughing out the figures with a kind of tool they call ‘subbia,’ which is pointed and heavy; it is used to block out their stone in the large, and then with other tools called ‘calcagnuoli’ which have a notch in the middle and are short, they proceed to round it, till they come to use a flat tool more slender than the calcagnuolo, which has two notches and is called ‘gradina’: with this they go all over the figure, gently chiselling it to keep the proportion of the muscles and the folds, and treating it in such a manner that the notches or teeth of the tool give the stone a wonderful grace. This done, they remove the tooth marks with a smooth chisel, and in order to perfect the figure, wishing to add sweetness, softness and finish to it, they work off with curved files all traces of the gradina. They proceed in the same way with slender files and straight rasps, to complete the smoothing process,[[163]] and lastly with points of pumice stone they rub all over the figure to give that flesh-like appearance that is seen in marvellous works of sculpture. Tripoli earth is also used to make it lustrous and polished, and for the same reason it is rubbed over with straw made into bunches—till, finished and shining, it appears before us in its beauty.[[164]]
CHAPTER III. (X.)
Of Low and Half Reliefs, the difficulty of making them and how to bring them to perfection.
§ 51. The Origin of Reliefs.
Those works that sculptors call half reliefs[[165]] were invented by the ancients to make figure compositions with which to adorn flat walls, and they adopted this treatment in theatres and triumphal arches, because, even had they wished to sculpture figures in the round, they could not place them unless they first constructed a standing ground or an open place that was flat. Desiring therefore to avoid this, they invented a kind of sculpture which they named half relief, and it is called ‘mezzo rilievo’ still among ourselves.
§ 52. Pictorial or Perspective Reliefs.
In the manner of a picture this kind of relief sets forth first the whole of the principal figures, either in half round or still greater salience, as may happen, the figures on the second plane partly hidden by the first, and those on the third by the second, just as living people are seen when they are assembled and crowded together. In this kind of half relief, for the sake of perspective, they make the most distant figures low, some of the heads indeed extremely low, and no less so the houses and scenery which are the objects most remote. By none has this species of half relief ever been better executed, with more observation, or with its figures diminished and spaced one from the other more correctly than by the ancients;[[166]] for they, who were students of the truth and gifted artists, never made the figures in such compositions with ground that is foreshortened or seems to run away, but placed them with their feet resting on the moulding beneath them. In contrast to this, some of our own moderns, over eager, have, in their compositions in half relief, made their principal figures stand on the plane which is in low relief and recedes, and the middle figures on the same plane in such a position that, as they stand, they do not rest the feet as firmly as is natural, whence it not infrequently happens that the points of the feet of those figures that turn their backs actually touch the shins of their own legs, so violent is the foreshortening. Such things are seen in many modern works, and even in the gates of the Baptistry and in many examples of that period. Therefore half reliefs of this character are incorrect, because, if the foremost figures project half out of the stone while others have to be placed behind them, there must be a rule for the retiring and diminution; the feet of the figures have to be on the ground, so that the ground may come forward in front as required by the eye and the rule in things painted. Accordingly the figures must be gradually reduced in proportion as they recede till they reach the flattened and low relief; and because of the harmony required it is difficult to carry out the work perfectly seeing that in relief the feet and heads are foreshortened. Great skill in design therefore is necessary if the artist wish to exhibit his ability in this art. The same degree of perfection is demanded for figures in clay or wax as for those worked in bronze and marble. Therefore of all the works which have the qualities that I indicate the half reliefs may be considered most beautiful and most highly praised by experienced artists.
§ 53. Low Reliefs (Bassi Rilievi).
The second species called low reliefs projects much less than the half reliefs; they have not more than half the boldness of the others, and one can rightly make in these low reliefs the ground, the buildings, the prospects, the stairs and the landscapes as we see in the bronze pulpits in San Lorenzo at Florence, and in all the low reliefs of Donatello, who in this art produced things truly divine with the greatest truth to nature. These reliefs present themselves easily to the eye and without errors or barbarisms, seeing that they do not project forward so much as to give occasion for errors or censure.