Fotospeed SLT20 Selenium Toner is a liquid toner which is supplied in a single part concentrate. Enhances image permanence and adds depth to shadow tones. It is specifically designed for the toning of Fiber and Resin Coated B&W papers to produce a wide range of subtle warm purple black tones or at higher dilutions for Archival Permanence techniques. The shade of the tone is adjusted by dilution and the length of time the print is allowed to stay in the working solution. The longer it remains in the solution the more toned it becomes. Resin coated papers can be slow to react with selenium, particularly the variable contrast papers. Papers with chlorobromide emulsions are the exception and will produce very effective results.