Sepia toners hypo-alum

The sepia/sulfide/hypo alum toners are the most stable as the selenium toners will only protect the shadow areas, not the highlights, unless toning is taken to completion, in which case the entire print will take on a color/tone, which will depend on the paper used. 

It is not necessary to make test strips with toners that are meant to work to completion, such as bleach and redevelop toners (for example, hypo-alum, sepia, etc.), as partial toning will result in an unstable final print. However, it may be desirable to tone a single strip of a correctly exposed and developed print and keep it among the toning swatches. 

However, by using a single-solution, sulfur-reacting toner such as Kodak T-la Hypo-Alum Sepia Toner or Kodak T-8 Polysulfide Toner (Formulas Toners Brown Toners) it is possible to convert the entire print at once. When this is done, the print cannot degenerate any further and instead of a ruined print the result is an archival print. 

With most sulfide/hypo-alum toners the color will be sepia to deep brown depending on the toner, paper, and developer used. However, polysulfide toner at dilutions of 1 100, has been found to protect most papers with little or no color shift. 

---