For photographic use, mixtures containing magnesium and nitrates are made much more fuel rich. The excess magnesium is volatilized by the reaction and burns in air providing additional light. In addition, the higher concentration of fuel results in a slower burn, providing more of a "poof" and less of a "bang" when ignited. A formula from 1917 specifies 5 parts of magnesium to 6 parts of barium nitrate for a stoichiometry of nine parts fuel to one part oxidizer. Modern recreations of photographic flash powders may avoid the use of barium salts because of their toxic nature. A mixture of five parts 80 mesh magnesium to one part of potassium nitrate provides a good white flash without being too violent. Fuel rich flash powders are also used in theatrical flash pots.