The recent discussions regarding image silver stabilisation through selenium toning strike me as rather pointless. There are undoubtedly more effective methods available for improving archival stability (gold, sulphur, Sistan). But even weak selenium toning is better than no toning at all when it comes to durability! Fineprinters use selenium toners primarily for entirely different reasons. The mode of action of this toner allows for a targeted increase in density in the shadow areas. Regardless of the dilution and temperature of the toner, the high silver densities are always attacked first. Selenium toning – Part 1 The recent discussions regarding the stabilisation of silver in the image through selenium toning seem rather pointless to me. There are undoubtedly more effective methods available for improving archival stability (gold, sulphur, Sistan). But even weak selenium toning is better than no toning at all in terms of durability! Fine printers use selenium toners primarily for entirely different reasons. The way this toner works allows for a targeted increase in density in the shadow areas. Regardless of the dilution and temperature of the toner, the high silver densities are always attacked first. Top: Untoned Bottom: Selenium-toned In addition to a significant gain in Dmax, the deep shadows appear more nuanced. Due to the higher dynamic range and a more or less pronounced shift in the image tone towards cooler (less green) shades, selenium-toned prints appear more brilliant. Changes in image tone depend on the emulsion composition of the paper and the developer used. The greenish tone of the image silver, which is not particularly appreciated by most photographers, can be shifted to more pleasing shades using highly diluted toner solutions. If the toner is also to reach the highest highlights before the shadow density decreases again, dilutions of 1+100 to 1+400 should be chosen. If only the shadows are to be enhanced, toning should be carried out for only a very short time (20–60 seconds) using strong solutions of 1+5 to 1+20. With such short, sharp toning processes, the process must be interrupted as quickly as possible. Wetting agents are not stop baths for selenium toners! By rapidly diluting the toner adhering to the layer and the paper felt with running water and gently rubbing the image side and reverse side with a cotton wool ball, the toner effect can be reduced sufficiently quickly. All papers are susceptible to selenium toning! Some tone more quickly; with others, toning is only perceptible when compared to an untoned sample. In any case, the print becomes more brilliant, and the blackness of the shadows increases visibly and measurably. To avoid complicating matters unnecessarily, it can be noted that warm-tone papers tone quickly with a distinct change in image tone, whereas with cool-tone papers the change in image tone is often only slight. Even with extensive toning in rich toners, surprisingly little seems to happen. If such papers are toned to increase archival stability, there is therefore no cause for concern. The extent to which the toning has actually progressed can only be determined once the print has been bleached. If a reddish-brown image remains in which even the highlights still exhibit sufficient tone, the objective has been fully achieved. If the highlights—and in some cases even the mid-tones—have been bleached out, then the toning was insufficient to provide the print with the highest possible protection against environmental influences. However, even then, a slight membrane has already formed around the silver grains in the highlights. In such cases, one speaks of ‘hidden selenium toning’. With warm-tone papers, the progress of the toning is easier to assess. If only the shadows are to be enhanced, toning should be very brief with a low dilution (1+5 to 1+20); if the image tone is to be shifted slightly, high dilutions are advisable, otherwise the shadow densities will decrease again before the highlights are reached by the toner. The warmer the image has been developed, the thinner the toner should be, otherwise the image tone will become significantly cooler.