Relation between development center distribution and chemical ripening of pure silver bromide emulsion grains was investigated by taking electron micrographs of gelatin-envelops surrounding the grains after exposing the grains and partially developing them to reveal the sites at which developable latent image specks had been formed. For a primitive (non after-ripened) emulsions at low intensity exposure, the edge site of tabular grains was the preferred site for the development center formation and the development process started from there projecting silver filaments. The number of centers was few. On the contrary in an after-ripened emulsion, at slightly shorter exposure time the flat tabular surface of grains was the preferred site for development center formation. For the after-ripened emulsion, differing from the primitive emulsion, developed silver specks did not form at edge site without much heavier exposure. The centers were numerous, and silver filaments were fine and short. Among triangular and hexagonal tabular grains of both primitive and after-ripened emulsions, there were some grains in which the corner of them was the preferred site for development speck formation.