Formulary's Copper Toner contains copper sulfate, potassium ferricyanide, and potassium citrate which results in an image toned with copper metal. The toner produces a variety of colors ranging from warm brown through coppery hues to chalk red. The exact color obtained depends on the length of toning time. The process is rapid and progressive. It is possible to remove the print from the bath at any stage of its toning. Although fiber based papers work best, resin coated papers will work nicely also. The chemicals contained in the kit are used to make two stock solutions, which are mixed in equal volumes to obtain the working solution. The stock solutions are stable for a reasonable period of time, but the working solution should be discarded after use.