Why a Life-Size Painted Face Looks Larger Than Life
And how an opaque body borrows the colour of the walls around it
Two chapters of the Treatise on Painting share this page, the first carried by a geometric diagram of a head. It argues that a face measured and then painted at that same size appears larger than the natural, because the profile drawn on the picture plane c f stands nearer the eye than the true cheeks a b, throwing the temples out to o r and creating the difference c o and r d. The second chapter holds that the surface of any opaque body takes on the colours around it: a white object set between a white and a black wall divides into light and shadow in the same proportion as the two walls.
On this page
Measuring a face and painting it to size makes it look too large
a b is the width of the face, placed at the distance of the picture plane c f, where the cheeks are; but it ought to stand back all the way to c. Then the temples would be carried into the distance o r by the lines a f and b f, giving the difference c o and r d, so that the shorter lines c f and d f make the face on the paper larger than the truth at a f and b f.
Diagram: plan of a head with the projection lines
A geometric diagram of a head seen in plan is drawn at the centre, with the eye at F and rays running to the outline lettered E, A, D, B, and the widths a b, c f and the distances o r marked to show the difference between the true face and its projection on the picture plane.
An opaque body takes colour from the walls around it
If a white object is set between two walls, one white and one black, the shadowed part and the luminous part of the object stand in the same proportion as the two walls; if the object is blue, do the same, taking black to shade it in the manner of the wall's shadow.