Understanding Neutron Radiography Reading V-Kodak Part 2 of 3

■ Nomogram Methods
In Figure 54, the scales at the far left and far right are relative exposure
values. They do not represent milliampere-minutes, curie-hours, or any other
exposure unit; they are to be considered merely as multiplying (or dividing)
factors, the use of which is explained below. Note, also, that these scales are
identical, so that a ruler placed across them at the same value will intersect
the vertical lines, in the center of the diagram, at right angles. On the central
group of lines, each labeled with the designation of a film whose curve is
shown in the Figure 47, the numbers represent densities. The use of Figure
54 will be demonstrated by a re-solution of the same problems used as
illustrations in both of the preceding sections. Note that in the use of the
nomogram, the straightedge must be placed so that it is at right angles to all
the lines--that is, so that it cuts the outermost scales on the left and the right
at the same value.
Charlie Chong/ Fion Zhang
Radiography in Modern Industry. Rochester, NY: Eastman Kodak Co. 1980