Abstract: Based on the study of the latent image distribution and Sabatier effect of iodide uniformly distributed emulsions and core-shell emulsions, a machanism of Sabatier effect was proposed.The surface latent image centers produced during the first exposure became hole trapping centers after adsorbing anions of developer and were bleached during the second exposure, so that a reverse image was formed.It was indicated that for a good Sabatier emulsion it should contain enough surface sensitivity centers as well as enough internal sensitivity centers, and they should be well matched.This machanism can be used to explain several results of Sabatier effect.

Key words: core-shell emulsion, latent image distribution, Sabatier effect