Development effects and the MTF of high-resolution photographic materials for holography

Abstract

Modulation transfer functions (MTF’s) of high-resolution plates Agfa–Gevaert Scientia 8E70, 8E75, 8E75B, and 10E75 have been determined. A strong influence of the development conditions was found and studied. Observations and models given in the literature on adjacency effects at low spatial frequencies were extended and verified for spatial frequencies up to 1500 cycles/mm. This was possible by the use of a new type of microdensitometer (MSSM) and because the optical MTF of these plates is close to 1. By use of very weak developers, an apparent increase of the MTF by factors up to 2 could be achieved. Because this enhancement occurred only in connection with very low γ, there is no gain of contrast in applications to microreproduction. The diffraction efficiency of holograms was not improved, but exposure latitude was increased. Development effects may alter reconstructed wavefields, and spatial filters may deviate considerably from their designs, especially when low-γ development is used to obtain wide latitude.