…learns sculpture sooner than the sculptor learns painting. But to return to the point of what has been said about bas-relief, I say that it is of less bodily fatigue than the full round, but of much greater investigation, since in it one must consider the proportion that the interposed distances have between the first parts of the bodies and the second, and from the second to the third successively; and if these are considered by you, the perspectivist, you will find no work in bas-relief that is not full of errors in the cases of the greater and lesser relief required for the parts of the bodies that are more or less near the eye. Such error will never occur in the full round, because nature aids the sculptor; and for this reason what he makes in the full round lacks so much of that difficulty.

There follows a mortal enemy of the sculptor in the full and the low relief of his things, which are worth nothing unless they have the light accommodated to them, similar to that in which they were wrought. For if they have the light from below, their works will appear poor, and above all the bas-relief, which almost cancels the knowledge of it under the opposing judgements. This cannot happen to the painter, who, besides having placed the limbs of his things, has converted himself into the two offices of nature, which are the greatest, and these are the two perspectives; and the third, of the greatest discourse, which is the light and dark of the shadows and the lights, of which the sculptor is ignorant, and is aided by nature in the manner in which she aids the other invisible artificial things.