The combination of Cobalt and Iron Blue toning creates violet to blue-violet image tones. The level of toning depends on the dilution and working time of the cobalt toner. With shorter toning, only sublte tones in the highlights are visible; with longer toning the shadows are also toned. The subsequent iron blue toning only works in the areas that were not yet reached by the cobalt toner.
The working solution of the cobal toner should be prepared immediately before usage and stays fresh for only about 60 minutes!
The amount of the individual chemicals is enough for between 2,5 - 5 liters toner solution. The concentrates have a practically indefinite shelf-life. The diluted toner solution will last for a few months and can be used until it is exhausted.