SCANNING ELECTRON-MICROSCOPY AND ATOMIC-FORCE MICROSCOPY OF FIBROUS GELATIN OBSERVED BETWEEN AGBR MICROCRYSTALS

Gelatin has been the only circumstance for silver halides to grow of p hotographic use. However structural analyses of gelatin adsorption on silver halide microcrystals have rarely been made with microscopic met hods. The present study shows the adsorption of gelatin on AgBr microc rystals with scanning electron or atomic force micrographs taken durin g the removal process of gelatin in photographic emulsions. Gelatin th in layers remained covering AgBr particles after most of the gelatin m atrix was washed out in large quantities of warm water with strong agi tation. The thin gelatin layers were again dissolved away and narrow s trands of gelatin remained only where AgBr particles were packed close . The diameters of gelatin strands decreased gradually from the end wh ere the strands adsorb on the surface of AgBr to reach the thinnest at the center. The smallest diameter observed in this study was about 20 nm, which must be a strand of many collagen helices. Two different me thods to remove gelatin (conventional enzyme decomposition followed by centrifugal separation or the present warm water dilution with agitat ion and decantation) were compared and the warm water provided better exposed surfaces of AgBr with little gelatin residue.