What we said about the pictures, to a certain extent applicable to the paintings created by the artist's hand: their best to consider too, with the proper distance. Only under this condition will feel you perspective and the picture will seem not flat, but deep and relief. It is useful to look at one and not two eyes, especially in the paintings of small size.
“It has long been known, wrote on this occasion, the English psychologist Century carpenter in the above-mentioned composition, which, with careful viewing of the painting, where promising conditions, light, shadows and General arrangement of parts is strictly correspond to the depicted reality, produce the impression of much more alive when viewed with one eye, not both, and that the effect is amplified when we look through the tube, eliminating all extraneous atmosphere of the picture. This fact is explained completely false. "We see one eye is better than two, " says Bacon, " because life perfume concentrate in one place and act with greater force".
In fact here is the fact that when we look with both eyes at the picture at a moderate distance, it is forced to recognize its flat surface; but when we look only one eye, our mind can easily succumb to the impression of perspective, light, shadow, etc. Hence, when we look closely, the picture becomes in a short time relief and may even reach the physicality of the real landscape. The completeness of the illusion will mainly depend on the faithfulness with which the reproduced picture on the actual projection of the objects on the plane... the Advantage of vision of one eye depends in these cases, because the mind is free to interpret the picture on his own, when nothing makes him see her as a flat picture.”
Reduced images with large paintings often give a more complete illusion of relief, than the originals. You will understand why this is happening, if you remember that reducing the picture is reduced it is usually a great distance from which to view an image, so the picture gets bumpy already at a close distance.