Blue toners, formulas

There are three ways to achieve cold tones. The first is through direct development of bromide paper. The second is through the gold-toning of a warm-tone chlorobromide paper. The third method is immersion in a blue-toning bath (Formulas Toners, Ansco 241 Iron Blue Toner). 

Those that replace the silver with another metal. The compounds produced are usually either ferricyanide (Formulas Toners Copper Toner, Dassonville T-5 Copper Toner) or iron (Formulas Blue Toners Ansco 241 Iron Blue Toner). These are also known as replacement toners. 

There are two reasons to tone prints One is to change the color of the image, the other is for longevity. While the two are not mutually exclusive—some formulas both change the color and protect the image—they are not always complementary. For example, prints treated with iron toners, while attaining a rich blue color, often will not last more than a few years. 

The classic formula for gold protective toning is Kodak GP-1 Gold Protective Solution. Like selenium toner, GP-1 not only protects the print but causes a minimum color shift. What shift there may be is toward a slight blue-black that some photographers find pleasing. With some papers, GP-1 will also improve separation in the highlights. 

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