Bernard Courtois , also spelled Barnard Courtois, (8 February 1777 - 27 September 1838) was a French chemist credited with first isolating iodine, making early photography possible.

By 1811 the Napoleonic Wars had made the government-controlled saltpeter business taper off since there was by then a shortage of wood ashes with which potassium nitrate was made. As an alternative, the