NBS-1952 Resolution Test Chart (T-40)

The NBS-1952 Resolution Test Chart is described in the NBS circular 533-1953 in the section “Method of Determining the Resolution Power of Photographic Lenses”. Design features of this target reduce edge effects, minimize spurious resolution and permit one pass scanning. The T-40 is offered on four standard substrates;  Chrome on Glass (CG) Chrome on Opal (OP) Photographic Paper (RM) and Photographic Film (TM).

The NBS method of using this chart to test lenses involves placing the chart at a distance from the lens equal to 26 times the focal length of the lens, resulting in a 25x reduction. The reduction effective cycles per mm is 12 to 80 c/mm.