Commentary on Plato's Timaeus

NATIONAL LIBRARY

A technical photographic calibration target or test chart is displayed within a rectangular frame. At the center is a series of concentric circles. Lines radiate from the center toward the corners and the middle of each side. Each quadrant contains geometric shapes, including squares and triangles, filled with parallel hatching lines of varying density and orientation. Quarter-circles with concentric lines are placed in the four corners of the frame. At the bottom center, there is a horizontal metric scale numbered from zero to ten.