Were you to speak only of painting on panels, I should be content to give the verdict against sculpture by saying: Whilst painting is more beautiful, more imaginative, and more resourceful, sculpture is more durable; and this is all that can be said for it. It reveals with little effort what it is. Painting seems a miraculous thing, making things intangible appear tangible, presenting flat objects in relief, and distant near at hand. Indeed, painting is adorned with endless possibilities that are not used by sculpture.
Painting extends over all the ten offices of the eye--namely, darkness, light, body and colour, figure and scenery, distance and nearness, movement and repose--all of which offices will be woven through this little work of mine. For I will remind the painter by what rule and in what manner he shall use his art to imitate all these things, the work of nature and the ornament of the world.
We know clearly that sight is one of the swiftest actions in existence, perceiving in one moment countless forms. Nevertheless, it cannot comprehend more than one thing at a time. Suppose, for instance, you, reader, were to cast a single glance upon this entire written page and were to decide at once that it is full of different letters; but you will not be able to recognize in this space of time either what letters they are or what they purport to say. Therefore, you must take word by word, verse by verse, in order to gain knowledge from these letters. Again, if you want to reach the summit of a building, you must submit to climbing step by step, else it would be impossible for you to reach the top. And so I say to you, whom nature inclines to this art, if you would have a true knowledge of the form of things, begin with their details, and don't pass on to the second before the first is well fixed in your memory, else you will waste your time.
Perspective is the rein and rudder of painting.
I say whatever is forced within a border is more difficult than what is free. Shadows have in certain degrees their borders, and he who ignores them cannot obtain roundness, which roundness is the essence and soul of painting. Drawing is free, since, if you see countless faces, they will all be different--the one has a long, the other a short nose. Thus the painter may take this liberty, and where is liberty, is no rule.