Determination of Crystal Habit of Fine Silver Halide Grains in Photographic Emulsions through Their Adsorption of Dyes

Abstract

A new method has been developed to determine the crystal habit, i. e., proportion of the area of (100) face to the total surface area of fine silver halide grains in photographic emulsions, Poo, on the basis of the difference in absorption spectrum between a dye on (100) face and that on (111) face of the grains. For this purpose a cyanine dye, 3, 3'bis(4-sulfobuty1)-9-methylthiacarbocyanine (dye 1), was used, since it exhibited the most notable dependence of absorption spectrum upon crystal habit of the grains among the dyes tested. Namely, dye 1 showed a double band with the absorption maxima at 600 and 525 nm on the (100) face and J band with the absorption maximum at 630 nm on the (111)face. The reflection spectra of thick liquid emulsion layer containing various amounts of dye 1 were treated by the Kubelka-Munk equation to give saturated amounts of the dye adsorbed to (100) and (111) faces of the grains, from which the value P₁₀₀ of was determined for each emulsion with an error of 10%.