1. Oxidation: Tissue sections are treated with periodic acid to oxidize 1,2-glycol groups to aldehydes. 2. Schiff's Reagent: The tissue is then exposed to Schiff's reagent, which reacts with the aldehydes to form a magenta or purplish-red compound. 3. Counterstaining: Often, a counterstain such as hematoxylin is applied to provide contrast and better visualize tissue morphology.
