A method for improving the contrast in photographic film materials

摘要

Described herein is an arrangement for correcting the contrast of X-ray images to reveal details which are not otherwise visible. The arrangement comprises a conventional illumination box (10) for illuminating an X-ray (12), a camera arrangement (14) for viewing the illuminated X-ray film (12), the camera arrangement (14) including a camera unit (18) having a lens (20) mounted in a light tight box (16), a processing unit (22), and display means (24, 28) for displaying an image with the corrected contrast. The contrast is corrected using the characteristic curve of the processed film material on which the X-ray image is recorded in accordance with the following equation:- <MATH> where E is the exposure, D is the density at exposure E, Ei is the exposure at the point of inflexion of the curve, Ds is the density at saturation, and alpha and beta are characteristics relating to the processed photographic material. <IMAGE>