The chart is ruled with 90 lines and spaces of gradually decreasing width. The width of lines and spaces are in logarithmic series, and their lengths are varied to assist counting. The charts have a base length of 100mm and are supplied on 0.175mm thick film.
Typically in use, the image is examined to determine the finest detail that can be distinguished. The finest resolved line is then counted to define the resolution of the device. Includes 6 charts, resolution table and instructions for use.