The Magic of Ferricyanide Bleaching

My back story, recently I had a Lith session, from that session some prints didn’t come out the way that I had imagined. Likewise with a darkroom session where I was testing out my home-made warm tone developer. (I have video and articles on this blog concerning both of those topics if you are interested.)

I think most folks after a darkroom print sessions, they tend to have some prints that didn’t work out the way they wanted. So instead of dumping those failed prints, set them a side for experimentation. So talk about the darkroom secret which started way back in 1884 – Farmers Reducer.

What is Farmer’s reducer ?

It goes back to 1884, the formula was named after Howard Farmer who made it popular at the time. It a combination of two parts. The first part Potassium Ferricyanide who is used as a bleaching agent and the second part Hypo –  sodium thiosulfate. The Potassium Ferricyanide also known as Ferri bleaches the silver in the image back to silver salt. The fixing action of the Hypo dissolves these salt. Reduction is best done in small steps as you can always repeat the step if not enough density is removed but you can’t add back the density! Density refers to how much silver is built up. So remember use with caution!

Uses of Farmer’s reducer

The true beauty of ferricyanide bleaching lies in its ability to control contrast and tonal range in photographic prints. Photographers can vary the strength of the ferricyanide solution and the duration of the bleaching process to achieve specific artistic effects. Here are some of the key advantages and applications of ferricyanide bleaching:

  • Farmers Reducer could be used to make a really dense negative thinner so it’s more easy to print (dense negatives lead to really long print times.
  • It can lift the highlights of your darkroom prints giving them extra sparkle and contrast. Brightening areas on a print or the entire print. I use a cotton bud/Q-Tip and small dish of Farmer’s reducer to do such delicate work.
  • It could also be used with careful brush work to thin out certain areas.
  • Or if you’re really good, you can even take care of dark spots on prints from scratches on the film.

Recipe

I’m using one part of Farmer’s reducer without the Hypo fixer part. After I’m finished bleaching the print or negative should be fixed again.

  • Potassium Ferricyanide 7.5g in 1 Litre of still water

Warning:  Potassium Ferricyanide can release toxic (deadly) cyanide gas if exposed to strong acid or high heat! Keep away from concentrated stop bath, acidhardeners, and be sure to clean all utensils of contaminants before use. Work with adequate ventilation. Please be careful!

Brightening up a Print

  • Using a print which that is fixed and dried – a normal finished print.
  • Bleaching: The print is immersed in a ferricyanide solution. Here, the potassium ferricyanide acts as an oxidizing agent, selectively reducing metallic silver ions within the image.
  • Washing: The print is thoroughly washed to remove excess chemicals and halt the bleaching process.
  • Fixing and Final Rinse: Finally, the print undergoes a second fixing bath and a final rinse to ensure the image is permanent and archival.

Video

 

Paper: Kodak Polymax RC

Recently I picked up a couple of boxes of Polymax from around 2005. It’s a great paper to print with and very useful for both traditional and Lith print. I really enjoy this paper more so than a lot of modern Ilford papers. The paper is easy to tone and manipulate.

Kodak Polymax II RC Glossy
Kodak Polymax II RC Glossy

Paper : Kodak Dekora

This is an ancient paper probably from the 50’s/60’s. Most likely made in Berlin by Beko at the time as it was common to rebrand or outsource papers especially becuase

Vephota,Agfa,Berolux Deko darkroom papers
Vephota,Agfa,Berolux Deko darkroom papers

 

 

 

 

The printer is Nathalie Lopparelli source

Conclusion

Ferricyanide bleaching, a time-honored technique in darkroom photography, empowers photographers and printmakers to exercise precise control over contrast, highlight detail, and tonal range in their prints. With its rich history and continued relevance in the digital age, this process exemplifies the enduring marriage of art and science that defines traditional photography. As photographers continue to explore and push the boundaries of their craft, ferricyanide bleaching remains an indispensable tool for realizing their artistic visions in the darkroom.

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