High resolution electron microscopic study of silver sulfide microcrystals formed on silver bromide emulsion grains

Silver sulfide specks formed on the (111) plane of AgBr are examined by high resolution electron microscopy and the relationships in atom arrangement at their interface are revealed on the basis of the lattice images observed for the silver sulfide specks as well as their orientation relative to the direction of AgBr crystal axis. Silver sulfide are in contact with AgBr (111) plane with one of the four different planes, (100), (102), (104), and (103). In every interfaces, the b-axis of the microcrystal of silver sulfide is parallel with the [112] axis of AgBr. The atom arrangements of both the crystals are, similar to each other at the interface and the lattice misfits between them are so small that the formation of the silver sulfide specks is considered to occur epitaxially on the AgBr (111) plane.