*Due to the chemical nature of this product, it is available for in-store pick up only. This selenium toner provides deep rich blacks in the purple spectrum. brown tones will be the most revealing on fiber -based papers. Warm tone papers usually produce the most visible effects. In order to judge any color changes, do not continually observe the print in the toner as this makes it harder to observe the subtle changes occurring. During the toning process, regularly compare this print to your reference print in the holding dish/tray. Working strength solutions will normally last for up to 6 months in full, tightly capped bottles, 1 month in half tightly capped bottles, and up to 7 days in an open tray. It is designed to be used at ambient room temperatures, nominally 20°C/68°F.