The earliest and simplest method consisted in using large pieces of white marble, shaped and put together (“_commesso_”) to form a sort of silhouette: the perspectives, folds of robes, and other details being defined by lines made, first, with a graving tool, and then accentuated by rows of holes, (smaller or larger, according to the importance of the particular line in the general composition), pierced with a trepanning drill. This is said to be _a trapano_, and is in fact the real _graffito_ work. These punctures were frequently very deep, and when filled up with a stucco, composed of pitch (_pecie navale_), resin (_ragia_), and pounded potter’s clay (_bolio macinato_), produced a surface hard, and nearly as durable, as the solid marble itself. In order further to heighten the effect, the pieces of white marble, making up the entire scene or figure, were inlaid against a piece of dark marble: generally black for the atmosphere, and red for the ground, upon which the figures were supposed to stand. In the ornamental friezes, framing these scenes and figures, marble of other colours very early began to be used. Then presently, these coloured marbles found their way into the picture itself; especially in the larger scenes, where yellow, for instance, was found useful to accentuate jewellery or ornaments. Take as an example, _The Massacre of the Innocents_ (Matteo di Giovanni), in which it is very largely employed. To this end also, black marble is twice introduced with startling effect: for _The Libyan Sibyl_ (Guidoccio Cozzarelli), and for the negro boy in _The Story of Jephthah_ (Bastiano di Francesco). It is undoubtedly true, that the finest effects are obtained, where there is least variety in colour, and where the artist has depended most entirely on simple line, and contrasts of white marble against black. A fine specimen of this treatment is _The Story of Absalom_ (Pietro del Minella). Here the figures, trees, etc., stand out with almost weird abruptness, as if they had been cut out of white paper. It must be borne in mind, however, (in spite of statements made to the contrary, and the fact that such methods were employed elsewhere later on),[232] that the marbles used on the Pavement were always _natural_, and _not artificially coloured_. The Duomo authorities appear to have had quarries, either of their own, or under contract to supply them regularly. We read of _nostro marmiera_[233] at Gallena, in the Val d’Elsa; of black marble, brought from _chasciano de le donne_ (San Casciano, near Radicofani);[234] and of red from Gerfalco in the Val di Cecina, near Massa Marittima.[235]