The Foma Fomatoner Indigo 2 x 250 ml is a liquid concentrate, one-bath sulfide-based toner for resin-coated or fiber-base black and white photographs. It will give your black and whites a blue tone. Toning occurs at room temperature (68 - 77° F / 20 - 25° C) and the length of time depends on the desired effect, but is generally from 1.0 to 5.0 min. One set is enough to tone about 21.5 sq ft (2 sq m) of paper, or about 40 8 x 10" (20.3 x 25.4 cm) prints. The Fomatoner is composed of 2 parts (bleaching solution A and toning solution B), both of which are diluted with water in a ratio from 1:1 to 1:4, with 1:2 yielding optimum results, to control image tone and toning speed. Water of low hardness, preferably distilled, is recommended. After being washed, photographs are placed into the bath of toning solution. Following toning, photographs should be washed thoroughly again, preferably in running water.