Photographers' Formulary Thiourea Toner for Black & White Prints (Sepia)

The Thiourea Toner for Black & White Prints from Photographers' Formulary contains the chemicals necessary to convert the silver in a B&W print to a rich brown sepia-like tone.

It is a two-step process to tone the print. The print first is bleached in ferricyanide-bromide bath, which makes the image disappear. The print is then redeveloped in a sulfide bath, which is combined with the Thiourea Toner. The print's end result is a beautifully toned sepia print.