Sulfide sepia

Sepia Intensification Bleach and redevelop sepia toners, such as Ansco 221 Sepia Toner or Kodak T-7a Sulfide Sepia Toner, are more effective than chromium intensifier and will provide maximum archival protection for your negatives. The reason for the latter is explained more fully in Chapter 10,Toning Prints Protective Toners, though simply put, converting an image from silver metal to silver sulfide makes the image as permanent as it possibly can be. 

Sulfide Sepia Toner For cold-tone papers... 

Bleach-and-redevelopment (B R) toners bleach the silver to a pale color and then redevelop it to a new color. Most two-bath B R toners are of the warm-tone sepia/sulfide-type... 

Caution. Sodium sulfide in solution smells like rotten eggs. The smell has been known to cause some people to have headaches. Use in a well-ventilated area outdoors works just fine. Also, sulfide can damage undeveloped sensitized materials such as films and papers in a darkroom. This is another good reason to use sepia toners outdoors. 

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. 

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. 

This formula is similar to Ansco 221 Sepia Toner, without the rotten egg smell associated with sulfide toners. 

Sepia tones are obtained by convening the silver to siher sulfide, and gold and platinum tones by replacing silver by these metals. 

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