Page:A Treatise on Painting.djvu/350

  you wish to know if your picture be like the object you mean to represent, have a flat looking-glass, and place it so as to reflect the object you have imitated, and compare carefully the original with the copy. You see upon a flat mirror the representation of things which appear real; Painting is the same. They are both an even superficies, and both give the idea of something beyond their superficies. Since you are persuaded that the looking-glass, by means of lines and shades, gives you the representation of things as if they were real; you being in possession of colours which in their different lights and shades are stronger than those of the looking-glass, may certainly, if you employ the rules with judgment, give to your picture the same appearance of Nature as you admire in the looking-glass. Or rather, your picture will be like Nature itself seen in a large looking-glass.

This looking-glass (being your master) will shew you the lights and shades of any object whatever. Amongst your colours there are some lighter than the lightest part of your model, and also some darker than the strongest shades; from which it follows, that you ought to represent Nature as seen in your looking-glass, when you look at it with one eye only; because both eyes surround the objects too much, particularly when they are small.  Rh