How does silver staining work?

Silver staining involves several steps described below. 

1. Fixation: Proteins are stabilized and any interfering substances are removed. 
2. Sensitization and Washing: The gel is treated with chemicals to enhance the proteins' reaction to silver and to prepare them for silver reduction. 
3. Silver Impregnation: Silver nitrate or ammoniacal silver is applied to the gel. 
4. Rinsing and Developing: The gel is rinsed, and the silver metal forms an image of the proteins in a formalin-fixed gel or tissue.