THE EFFECT OF GELATIN ON SILVER HALIDE STRAIN IN PHOTOGRAPHIC FILMS

X-ray diffraction techniques have been utilized to study strain and residual stress within coatings of silver halide dispersed in a gelatin or gelatin and latex matrix. Compression of the silver halide perpendicular to the film plane due to gelatin shrinkage is observed to occur as the coated film is exposed to low relative humidity (RH) environments. At 0% RH, the silver halide in the gelatin and gelatin plus latex films showed -0.77% and -0.62% strain, respectively. Residual stress analysis was performed in an ambient environment. Residual stress calculations found a triaxial stress state in both gelatin and latex-modified gelatin films. A mechanism for drying stress-induced optical density artifacts is proposed based on critical strain determination and strain recovery experiments.