THE COMPARATIVE EVALUATION OF FILM-SCREEN COMBINATIONS

증감지와 필름에 따른 방사선상 변화에 대한 연구

This study was to compare the quality of image by different screen and film combinations. Using the sensitometer measured the speed and average gradient of blue sensitive films and orthochromatic films. The films was combined with rare earth screen LR, LM, LF and conventional screen OM, OH, XOR, OKa and exposed the step wedge to impulse 2, 3, 4, 6, 10, 15, 24,3 8, 60 and measured the density. The following results were obtained: 1. The density of film and film-screen combinations showed significant difference, then in film-screen combinations was significantly different by the screens than films. 2. The speed of blue sensitive films was little different, the TMG of orthochromatic films produced high speed, and the AX film was high average gradient. 3. The relative speed of film-screen combinations showed significant difference, and was high in the OKa of the conventional screens and in the LR of the rare earth screens, especially that of LR screen in the combination with blue sensitive films was high. 4. The average gradient of film-screen combinations showed no significant difference, and was high in the OKa screen and LR/OG combination, and that of OKa/AX combination was highest. 5. The latitude of film-screen combinations showed significant difference by screens, and was high in the LM screen in combination with blue sensitive films and in the OM screen in combination with orthochromatic films. 6. The subject contrast of film-screen combinations showed significant difference by screen, and was high in the LR screen in combination with blue sensitive AX film and orthochromatic TMG film.