Formulary's Polysulfide Toner yields rich, dark brown and is similar to Kodak T-8. The toning bath contains potassium polysulfide (liver of sulfur) and sodium carbonate. Formulary Polysulfide Toner, like Hypo-Alum Toner, deposits silver sulfide on the image. The difference between these two toners is the depth of the resulting brown color. Polysulfide Toner gives a rich, dark brown tone while tones obtained using the Hypo-Alum are much lighter. Both toners give permanent images. Toning with the Polysulfide Toner takes about 15 to 20 minutes at room temperature. This toner works well on all papers except Kodabromide paper. The chemicals in this kit are used to prepare 1 liter of working solution, which has a capacity of about 35 8x10" prints. A second package of sodium carbonate to be used to partially rejuvenate the spent working solution is included. The working solution is stable for extended periods of time.