[Measurement of the modulation transfer function of film-screen combinations with a lead scanning pattern]

A lead bar pattern, with continuously varying frequencies, has been used for measurement of modulation transfer functions of screen-film combinations. Although the highest usable frequency of the grid is only 3.4 mm-1, evaluation of the first as well the third harmonic permits the expansion of the frequency range up to 10.2 mm-1. Automatic evaluation of the images of the bar pattern gives reproducible results. These are presented.