Unreliability of photographic Emulsions on Glass for Recording Distances and a Method of Minimizing this Defect
D. Cooksey, C. D. Cooksey · Physical Review · 1930
Superficial motions of double coated emulsions were investigated by Schlesinger's ink dot method. Also the positions of developed images with respect to corresponding latent images were studied for singly coated plates. Apparently there are stresses in undeveloped gelatin emulsions that can be relieved before plates are used for photographic purposes by soaking them in water followed by dehydration in alcohol, thus greatly enhancing their reliability for recording distances. This process we have termed normalizing. The maximum observed change in a distance between images, in their latent and developed states on a singly coated plate was 9\ensuremath{\mu} without normalizing and 2.2\ensuremath{\mu} with normalizing. The average change was likewise reduced to about one quarter. The advantage of normalizing is emphasized by the results reported in another paper.