Say goodbye to cyanide: a less toxic approach to fixing wet collodion plates

Elizabeth Graves shares her favorite developer recipe for wet collodion plates, which works well with a sodium thiosulfate fixer.

Writer and photography / Elizabeth Graves

When I attended a workshop to learn how to make plates using the wet plate collodion process, I was told that potassium cyanide is the best fixer for plates. Our instructor provided the option of using sodium thiosulfate, so we could see for ourselves that the thiosulfate plates were lower contrast and darker than those fixed with cyanide. I was persuaded that cyanide was superior, and used cyanide as a fixer whenever I rented the collodion darkroom at RayKo Photo Center.

When it was time to set up a darkroom at home, my “green” California consciousness forbid me from buying potassium cyanide. I’m someone who won’t buy conventional bleach for my laundry or toxic scrubs for my kitchen! I dedicated myself to trying to maximize the less toxic choice I had made, but it felt like a compromise.

Was I dooming myself to dark plates forever?

Questioning my habits

Wet collodion image of a sake bottle
A cropped example of a wet collodion positive on metal developed with Waldack’s developer Formula No. 1 and fixed with sodium thiosulfate

If you have tried to grill foods of different densities and moisture levels beside each other, you may have noticed that you can’t cook significantly different foods together. The cooking temperature will be optimal for one food at the expense of another. Marinated eggplant is not a better or worse food than a potato, but the eggplant will be more delicious if the grill was hot when you put it on, while the potato will dry out. The hot grill’s setup in this instance is optimized to favor the eggplant.

I wondered: had my working methods been optimized for cyanide, rather than thiosulfate? Was the cyanide result at the workshop better because every other choice I made was rigged in its favor?

In a word, YES. Through experiments, I found that I could get better results with sodium thiosulfate if I exposed the plates slightly longer and developed them significantly longer than I would while using cyanide.  This adjustment allowed me to enjoy an improvement in the contrast of my plates right away.

This inspired me to question my other practices, and in particular, my developer.  Was I choosing the right developer for my working methods?  I decided to review my options.

Developer Research

My developers had all seemed about the same with cyanide, but hoped that I could improve my results with my less toxic developer by experimenting with new recipes. I knew from reading old alt process books that there are MANY recipes, and that some photographers used different recipes for different conditions (hot weather, dry air, etc.) and different effects.  It seemed likely I could find one that would give me different results.

Sake bottle label (wet collidion image detail)
Detail showing the label on a sake bottle

In chapter 16 of John Towler’s 1864 book, The Silver Sunbeam (, I found a series of promising developer recipes, and began experimenting. In particular, I tried two of Waldack’s Formulas for Collodion Positives: “Formula No. 1. For Dead-Whites” and “Formula No. 2. For Brilliant and Metallic Whites.” The titles alone suggested that I was on the right path, and some time in the darkroom quickly proved that adjusting the developer provided better results than I’d had with previous recipes when using my less toxic fixer of choice.

Formula No. 1 turned out to be my favorite.  With one ingredient substitution, it gives me mirror-silver highlights if my exposures are long enough.

Waldack’s Formula No. 1 as I use it


The 1864 recipe is a bit difficult to interpret, with its list of dachms, ounces, and grains.  My version of the recipe is as follows:

  • sulphate of iron (ferrous sulfate) 12 grams
  • water (distilled) 185 ml
  • acetic or nitric acid (I prefer nitric), 16 ml
  • alcohol (100 proof laboratory grade ethanol) 12 ml
  • nitrate of potassa (potassium nitrate, “saltpetre”) 2g

I dissolve the ferrous sulfate into the water, add the acid and alcohol, stir for a long time, and then add the potassium nitrate and stir even longer. Extensive stirring is required to dissolve the ferrous sulfate. The solution must be filtered through a coffee filter or woven cotton pads to remove any remaining solids before use.


I usually prepare this developer the night before making plates, but have had good results by mixing it up a week in advance also.

Mirror bright

Using a pale backdrop, a bright bottle, a bank of UV lights, and a four minute exposure with my homemade camera at f9 on my process lens, I was able to push my plates into a new range of results, which included actual mirror-silver density in certain sections of the plate.
Reflection of the same detail, showing a metallic silver reflection on the text characters

(The images here show the final, varnished plate. Varnishing darkens the surface of a plate significantly, and tints it, often toward yellow or tan. When you see a blue or milk-white collodion plate on the Internet, it is likely unvarnished. Violet or green images are sometimes unintended digital exposure adjustments. I photographed the plates with my phone to illustrate this article, and had to choose from among several odd tints caused by differences in ambient lighting and room color, ranging from yellow to “weak latte.”)


Experimenting with a new developer allowed me to produce plates which have a tonal range and ‘look’ I’m after. I’m glad I was willing to revisit all of the elements of my working method – exposure time, developer time, developer recipe, and fixer – to expand my options for working with collodion.

Elizabeth Graves is an artist working with cyanotype, vandyke and collodion and a keen experimenter with all sorts of alternative photographic processes.

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1 thought on “Say goodbye to cyanide: a less toxic approach to fixing wet collodion plates”

  1. If you have a copy of the Scully & Osterman Basic Wet Collodion Manual. The use of potassium nitrate and nitric acid is described in the development section. These additives, along with sugar, have been known and used since the modern revival started in the 1990s. They are easy to use and we suggest that wet platers experiment to find the color they prefer given the fixer they use.

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