Abstract: The Study of stratified iodide distribution in a single silver iodobromide tnicrocrystal by ultrathin sectioning and X-ray line scan were carried out. The result coincides with anticipated iodide distribution. X-ray line scan acrossthinner sample provides a relative accurate technique to determine stratified structure containing different amount of iodide. It will help us improve the preparation of silver iodobromide emulsion. The space resolving power of X-ray source and thickness of ultrathinsection in the experimental condition of this work were discussed.As a check test, the ultrathin section, of a commercial color film was prepared and the structure of microcrystals in the ultrathin section was determined by X-ray line scan.

Key words: ultrathin sectioning, X-ray line scan, stratified structure, iodide distribution, silver halide microcrystals