Measurement of the Modulation Transfer Function of Radiographic Systems Containing Fluorescent Screens

Experimental and theoretical considerations indicate that the simplest method of obtaining the modulation transfer function of screen-film systems is by calculation from the measured line spread-function. However, care must be taken, since the sweeping tails of the line spread-function and the presence of development effects can introduce a considerable error in the transfer function calculation. An experimental method involving a narrow slit is described. Results are shown for three typical screen-film systems having different resolutions.