Understanding Neutron Radiography Reading V-Kodak Part 2 of 3

■ Example 3: The types of problems given in Examples 1 and 2 are often
combined in actual practice. Suppose, for example, that a radiograph was
made on Film X (See Figure 47) with an exposure of 20 mA-min and that a
density of 1.0 was obtained. A radiograph at the same kilovoltage on Film Y
at a density of 2.5 is desired for the sake of the higher contrast and the lower
graininess obtainable. The problem can be solved graphically in a single step.
The reading on the outside scale for D = 1.0 on Film X is 38. The
corresponding reading for D = 2.5 on Film Y is 420. The ratio of these is
420/38 = 11, the factor by which the original exposure must be multiplied. The
new exposure to produce D = 2.5 on Film Y is then 20 x 11 or 220 mAmin.
Charlie Chong/ Fion Zhang
Radiography in Modern Industry. Rochester, NY: Eastman Kodak Co. 1980