Bellini Potassium Bromide, 250 grams

Potassium bromide is used as a restrainer in many black and white developer formulas, especially those containing hydroquinone, pyrocatechin, or pyrogallol. It improves differentiation between exposed and unexposed crystals of silver halide, and thus reduces fog during development.

When used in paper developers, it also reduces contrast and provides a warming effect.

It can also be used as a bleach additive or toner additive.

It has a molecular formula KBr.