First it is necessary to know what this sort of imitation is, and to
define it.
Definition:
It is an imitation made with lines and with colours on some plane
surface of everything that can be seen under the sun. Its object is to
give delight.
Principles which may be learnt by all men of reason:
No visible object can be presented without light.
No visible object can be presented without a transparent medium.
No visible object can be presented without a boundary.
No visible object can be presented without colour.
No visible object can be presented without distance.
No visible object can be presented without an instrument.
What follows cannot be learnt, it is born with the painter.
_Nicholas Poussin._