USAF Test chart Two patterns are available, 0-7 and -2-7, produced in accordance with the USAF Resolving Power Test Target. The most popular range is 0-7 group, with 6 elements per group, an element consisting of two target patterns of 3 lines at 90? to each other, the line space ratio being equal. These charts are produced as a chrome surface image on glass plate. Qty :