Influence of Secondary Radiation on Image Quality

Abstract

On the basis of observations concerning non-screen films and xerox plates a theory is proposed as to how the image quality is impaired by secondary radiation. The theory includes an explanation of why xerox plates and industrial roentgen films of a high silver content are less affected by secondary radiation than conventional roentgen films.

Influence of Microscopic Mottle on the Definition of Small Image Details

“…This after-treatment consisted in contact copying the double-emulsioned original film onto a single-emulsioned finegrain film (Kodalith Ortho Type 3). In this copying most of the granularity of the original film is lost, the mottle still being preserved (SELIN & REICHMANN 1979). The elimination of the granularity makes evaluation of the mottle considerably easier.…”

“…The exposure arrangement, including tube, grid, cassette, and devices for measurement of tube potential and (relative) incident radiation dose, appears in Fig. 2, p. 554 in SELIN & REICHMANN (1979).…”

“…Part of this noise appears directly in the films as density fluctuations, but density variations may also appear that are so small as to escape detection by the unaided eye. A technique for evaluation of this microscopic noise has been described previously (SELIN & REICHMANN 1979). A secondary-ray grid (44 lead bars/ern) was exposed, the resulting image being copied and magnified x 32.…”

Medichrome Film as an Alternative to Silver-Free Recording Systems

“…The Medichrome films were inspected according to principles to be described. The second mode of inspection was per formed according to SELIN & REICHMANN (1977). The roentgen films were copied onto a fine-grained film.…”

“…However, accumulating evidence indicates that there is another property of the film which is not correlated to the parameters of the characteristic curve in any simple way, namely the number of grains per unit area (DAINTY & SHAW 1974, SELIN et coll. 1975, SELIN & REICHMANN 1977, REICHMANN et coll. 1978).…”