Many things affect the readability of micrographic images. One of them is the resolving power of the camera/film/processing system. Resolving power is easily measured by the following three step procedure:

1. A National Bureau of Standards 1010A (equivalent) microcopy chart is filmed. The chart consists of 26 paterns of closely spaced parallel line sets. Each set has two groups of five parallel lines arranged perpendicular to each other with a numeral printed beside each set. Each of the 26 sets is a different size.
2. The processed film is examined under a microscope of approximately 100X magnification to determine which is the smallest set (largest numeral) that shows all ten of the line pairs to be clearly separated.
3. The resolving power of the camera/film/processing system is calculated by multiplying the camera reduction ratio by the numeral printed beside the line set selected in Step b. Resolving power is stated in terms of line paires per millimeter.

Reprinted with permission from:
MicroD International
14901 Judcial Rd.
Burnsville, MN 55306 USA