The Sharpness Indicator is made up of test-targets with concentric circles printed on a Reference Field Level background. The background has the same reflectance as the average reflectance of the targets. When a target appears to blend with the background, it indicates that the target is beyond the sharpness of the system being tested.

The concentric circles that make up each of the test targets on the Sharpness Indicator are calibrated in the degree of sharpness (DS).