The toner concentrate VIRADON is used to modify the tone of a print. The effect depends on toner concentration and composition of the silver image. Since the keeping properties of toned prints are even better, VIRADON can also be used for image stabilization. Dilute 1:24. Immerse print for 2 – 10 minutes. [ online directions]
Polysulphide toners act on all densities equally, thereby providing color change and protection to the image. The original, 1930s formula included selenium but the later formulas removed that because of environmental impact awareness . Dilutions of 1+25 Viradon mixed with a working dilution of Selenium toner results in image tones comparable to the original Viradon. Polysulfide toners work faster as they become exhausted or diluted. This is one reason for using the sulfite “stop” bath before washing. Also, very diluted or mostly exhausted Polysulfide toner can leave an overall yellow or peach-colored stain.
This speeding up of toning means that as you wash the print after toning, the toning increases! To arrest this you can use a 10% solution of Sodium Sulphite; better, use a 2% colution of Kodak Hypo Clearing Agent (HCA).
To assure even toning and ‘stopping’ the print must be agitated immediately upon being put into the solution. This agitation must be continued, otherwise the print will become smoky, or milky. The Viradon will pick this up. It must be filtered, or discarded.
Agfa failed; with that, Viradon went off market. It was similar to Kodak Polytoner, Kodak Brown toner. None of these are are the market. Kodak’s T8 toner is a substitute that can be made by those with proper skill and workspace:
Water: 750ml Potassium Sulphide: 7.5g Sodium Carbonate monohydrate: 2.5g Water to make: 1 litre
Kodak Rapid Selenium toner and Kodak brown toner can be combined to give a single-solution toner which works rapidly at room temperature. This combination toner is recommended for Kodak warm tone papers.
Kodak Rapid Selenium Toner 17.0 ml Kodak Brown Toner 75.0 ml Kodalk Balanced Alkali 30.0 grams Water to make 1.0 liter Tone Prints for 3 minutes at 70F Capacity: 80 8x10 prints per gallon Replenisher: Selenium Toner diluted 1:5 add 30.0 ml per ten 8x10 prints Capacity with replenisher: 150 8x10 prints per gallon.
Image Stability, Keeping Quality: Selenium Toner
Lee, Wood, and Drago published a paper in 1984 about the stability properties of a variety of toned images finding that selenium acted well as a protective treatment; however, the Image Permanence Institute at Rochester Institute of Technology investigated the action of selenium, they found that selenium worked well for high density areas (shadows), but did not convert the mid-tones and highlights well. Kodak investigated the problem, finding that field users were having unusually stable prints even though lab tests couldn’t support this field result.
The answer was in the quality of the chemicals used to make the formulations. This is one time where lower quality chemicals (GPR) were acting better than lab grade (AR). The consumer toners contained sodium thiocyanite; the effectiveness of the selenium toner as a image preserver was really because of the active sulphur compounds within the general purpose practical grade chemicals. Most trained archivists know this.