Formulary's Nelson Gold Toner is similar to Kodak T-21 and is unmatched in its versatility. Tones range form just a hint of warmth to rich sepia browns. Toning can be stopped at any time between 5 and 20 minutes. Final images are permanent and are formed by a combination of silver sulfide and gold. The toner keeps almost indefinitely and its capacity is extended by adding small amounts of gold chloride solution, which is included in the kit. The toner is relatively inexpensive per print. One liter of solution is used to tone about 300 to 400 8x10" prints (with replenishment), depending upon tones desired. The satisfying results of this toner have made it a popular toner over the years. The chemicals in this kit are used to prepare a working solution, and the kit contains sufficient gold chloride from a replenisher solution.