Contrast-Transmission Functions Determined Experimentally for Asymmetrical Images and for the Combination of Lens and Photographic Emulsion

Abstract

Equipment is described for obtaining the contrast-transmission curves for two cases not realized by previous designs. First, for asymmetric images, the phases as well as the amplitudes of the Fourier transforms are measured. The relation between the image asymmetry and the acutance of an edge is also discussed. Second, the convolution of the functions of the lens and the photographic emulsion gives the transmission function of a complete system. The principal optical arrangement is undisturbed for the two determinations. In the second case, modulation of the flux is accomplished by polarizers. The differences between the highest and lowest densities are presented directly since density relates well to perception by the eye. These data are then recalculated to light-intensity functions in the emulsion, extending the concept of transmission functions to the emulsion. Some experimental results are given for Panatomic-X emulsion, and limitations of the methods are discussed.