There are three basic kinds of chemicals used in a darkroom to create photographic prints they are  'Developer', 'Stop Bath' and 'Fixer'. These are mixed with water, and used in this order when developing a photographic print.

Each chemical should be stored in a plastic or glass bottle that is opaque or semi-transparent, brown or black. Preferably the bottles should also be stored in a cupboard to ensure no exposure to light when the darkroom is not in use.

Always use tongs and/or gloves when handling theses and don't swap bottles or trays. Label each one for the particular chemical to prevent cross contamination.

Darkroom chemicals can be purchased from any good Photography Supplies Store or for more information about working in a dark room see: Darkroom Setup List.