Proportion: certain objects are smaller than others to create depth; the objects are all relatively small and proportionate to each other. Composition: bolder colors seem to leap off the page, whereas lighter colors appears to fall back; almost all the objects are vertically (or almost vertically) placed so the eye travels up and down when looking at the piece; there is balance of shape and color. Answer will vary for the artist's message but should be backed by reason.
Well the artist David Hockney believed that Johannes Vermer and other used these devices such as the camera obscura to help them achieve their perceptive in achievement
