From Talbot to Le Gray, Greenlaw, and Pélegry
For my Pictorial Whispers project, I went on a multi-year journey through calotypes, waxed paper negatives, salt printing, and other historical printing workflows. I was not looking for a process because it was old or romantic. I wanted to understand how each workflow behaved chemically, visually, and practically.
That search took me through more than a dozen calotype and paper-negative variations, from Talbot’s original 1840 process to later French and British refinements. I also explored different printing methods and tested how these negatives behaved when printed in salt, platinum, palladium, and other historical processes.
Over time, the answer became clear. The calotype was not merely compatible with salt printing. It was made for it.
To understand why, we need to look at the chemical evolution of the calotype paper negative. This history is not just about names and dates. It is about photographers trying to solve real problems: instability, fogging, weak density, fragile papers, uneven coating, difficult travel use, and the challenge of making a paper negative that could print beautifully.
The most important lesson is this: most so-called “new” paper-negative processes were not completely new chemical systems. They were variations on Talbot’s original idea. Taylor and Ware make this point clearly in their study of the calotype from 1840 to 1852: the core chemistry remained silver iodide in paper, sensitized with silver nitrate, exposed to light, and developed with gallic acid or a related developer.
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Talbot and the Birth of the Calotype
William Henry Fox Talbot’s calotype process was announced in 1841, based on work he began in 1840 and had been working on since the early 1830s. It was the first practical paper negative process that could create a latent image in the camera and then bring that image out by development.
Talbot’s process used four key chemicals:
- silver nitrate
- potassium iodide
- acetic acid
- gallic acid
The workflow had three main stages: iodizing, exciting, and developing. First, the paper was treated so silver iodide formed in the fibers. Then it was made sensitive with an exciting solution containing silver nitrate, acetic acid, and gallic acid. After exposure, the latent image was developed.
Talbot’s goal was speed. He wanted the process to be sensitive enough for camera work. But the tradeoff was instability. The excited paper could fog, stain, or spoil quickly. In practice, the photographer had to work carefully and within a short window.
This became the central problem for everyone who followed Talbot: how do you make the paper negative more reliable without losing its beauty?
The Scottish Refinements: Control Over Speed
Many histories jump too quickly from Talbot to the French refinements. That misses an important part of the story. Between 1842 and 1846, Scottish photographers and writers helped make the calotype more practical.
William Holland Furlong created a more controlled method for iodizing the paper. Instead of Talbot’s two-step method, Furlong used silver iodide dissolved in strong potassium iodide. When water was introduced later, silver iodide re-formed in the paper. Taylor and Ware describe this as a chemically elegant answer to problems in Talbot’s iodizing stage.
George Smith Cundell helped by making the instructions clearer and by recommending weaker exciting solutions. This was important because Talbot’s strong solutions could stain or embrown the paper. Cundell accepted a slower process in exchange for better control.
Dr. John Adamson also helped clarify the role of gallic acid. He recognized that gallic acid caused trouble when included too early in the exciting solution. By keeping gallic acid mostly for development, the process became more stable.
This is one of the most important lessons in the chemical evolution of the calotype: progress did not always mean faster. Often, progress meant slower, cleaner, and more reliable.
Blanquart-Evrard: Important, But Often Overstated
Louis-Désiré Blanquart-Evrard is an important figure in the history of photography, especially in the spread of paper photography in France. But his role in the chemical evolution of the calotype negative should not be overstated.
Taylor and Ware argue that Blanquart-Evrard’s 1847 process was essentially Talbot’s calotype process, with only a small addition of potassium bromide. They also point out that removing gallic acid from the exciting bath and using gallic acid mainly as a developer were not truly new ideas by that time.
That does not make Blanquart-Evrard unimportant. His role in popularizing and standardizing paper photography mattered. But chemically, the more important French breakthrough came from Guillot-Saguez.
Guillot-Saguez: The True French Breakthrough
Dr. Guillot-Saguez made one of the most important changes in the calotype workflow.
Instead of forming silver iodide during the iodizing stage, he treated the paper with potassium iodide alone. The silver nitrate was added later during the exciting stage. This was a major simplification because it moved the essential silver salt into a later, more controllable step.
His method also created a useful visual indicator. Potassium iodide on the paper could oxidize slightly and produce a violet or purple color. On starch-sized French papers, this could appear blue. When the exciting solution fully penetrated the paper, that color disappeared. This gave the photographer a visible sign that the paper had been properly excited.
This was a major practical advance. It simplified the preparation of paper and laid the groundwork for Gustave Le Gray’s waxed paper process.
Le Gray and the Waxed Paper Negative
Gustave Le Gray did not invent a completely new photochemistry. His waxed paper process remained part of the calotype family. But he made the paper negative far more useful.
Le Gray’s key move was to wax the paper before sensitizing and exposure. This strengthened the paper, reduced tearing, improved transparency, and reduced light scattering from the paper fibers. Taylor and Ware note that wax gave the paper more strength and allowed long immersion in the chemical baths.
This mattered visually. A plain calotype has a beautiful softness, but the paper fibers can scatter light and reduce clarity. Wax changes that. It fills the paper structure and makes the negative more transparent. The image still has the atmosphere of paper, but it gains more clarity and printing power.
It also mattered for travel. Le Gray’s waxed paper could be prepared before departure, carried into the field, exposed, and developed later. Sensitized waxed papers could keep for several weeks without loss of speed, and exposed negatives could be developed later when convenient. I have found this to be true in my work as well.
For a photographer working away from the darkroom, this was a major step forward in the mid 1850s. I experienced the same benefit in my darkroom in 2026 as I worked my way through all of the calotype workflows.
Greenlaw and the Hot-Climate Paper Negative
Alexander Greenlaw belongs to a slightly later part of the story, but he matters because his name became attached to a plain-paper version of the Guillot-Saguez method used in India.
Taylor and Ware note that by 1856, the Guillot-Saguez plain-paper method was found useful in hot climates by photographers in India, including Greenlaw. His name remained connected with this version of the calotype into the 20th century.
This is an important distinction:
- Le Gray used pre-waxed paper.
- Greenlaw used a dry plain-paper workflow and waxed after processing.
That difference matters because pre-waxing changes how the chemistry enters the paper. Greenlaw’s line kept the paper more open during sensitizing and exposure, then used waxing later to improve transparency for printing.
If I don’t need to pre-make calotypes in advance, I frequently don’t pre-wax the paper and follow the Greenlaw workflow. In both cases, Greenlaw and Le Gray, I keep a large batch of Iodized papers on hand to sensitize and expose on demand. I should note the iodizing chemistry is different between the pre-waxed Le Gray workflow and the plain paper Greenlaw workflow. Also, with Greenlaw, I am forced to sandwich the calotype between glass plates in my wet plate/dry plate holder, and with Le Gray calotypes, I can use my film holders because the paper is very flat and behaves much like sheet film.
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Pélegry: The Late Paper-Negative Refinement
By the time Arsène Pélegry published his method in 1879, wet collodion on glass had already become the dominant photographic negative process. The British Museum notes that by 1861, the calotype had been superseded by wet collodion.
So Pélegry should not be described as the final step before photographers favored collodion. He came after that shift. But that does not make him irrelevant. It makes him more interesting.
Pélegry represents the late survival and refinement of the paper negative for artists, travelers, and landscape workers who still valued the look, portability, and practical advantages of paper.
His 1879 book was written for painters, travelers, and tourists. That alone tells us something. He was not trying to compete with commercial studio collodion work. He was trying to make paper photography practical for people working outside the studio, away from heavy equipment and fragile glass plates. In the introduction, Pélegry argues that paper is especially suited to travel because it avoids the breakage, weight, and handling problems of glass.
The Pélegry Workflow in Plain English
Pélegry’s process is best understood as a dry paper-negative workflow with careful iodizing, sensitizing, washing, tannin preservation, pyrogallic development, fixing, and post-oiling.
He did not rely on pre-waxing like Le Gray. In fact, Pélegry specifically says he used oiling after development, not before sensitizing, because untreated paper absorbs the chemical baths more easily.
His workflow can be summarized like this:
1. Iodize the paper
Pélegry prepared an iodizing bath using clarified whey, potassium iodide, potassium bromide, and lactose. His listed quantities were intended for forty sheets around 21 × 27 cm. The text from the 1879 book gives the iodizing bath as clarified whey, potassium iodide, potassium bromide, and powdered milk sugar. The paper was immersed and dried.
This was not a quick brush-on procedure. It was a full immersion workflow, which helped give more even chemical penetration.
2. Store the iodized paper
Once dried, the iodized papers could be stored. Pélegry states that papers sensitized six months after iodizing still gave excellent results.
This is one of the reasons the process mattered. It separated paper preparation from field exposure.
3. Sensitize the paper
For sensitizing, Pélegry used a silver nitrate bath with citric acid. He also prepared a preserving bath containing dextrin, tannin, alcohol, and gallic acid. The process used multiple trays: silver bath, water, salted water, clean water, and tannin bath.
The key idea was not just sensitizing the paper. It was sensitizing, washing away free silver nitrate, and then preserving the paper so it could be used dry.
4. Wash carefully
Pélegry emphasized careful washing. He specifically wrote that the conservation of sensitivity depended on the perfection of the washings.
This is a critical point. The process was not magic because tannin was present. It worked because the free silver nitrate was controlled and the paper was stabilized before use.
5. Use the tannin bath
After washing, the sheet went into the tannin bath for one or two minutes before drying.
Modern conservator and calotypist Wlodek Witek describes the essence of the Pélegry process as meticulous rinsing of sensitized calotype paper followed by a special preserving bath. Witek also notes that sensitivity could be retained for at least three months and that development could be delayed after exposure.
6. Expose dry
Pélegry’s process was a dry paper process. This made it valuable for travel. The paper could be prepared ahead of time, carried in a portfolio, exposed in the field, and developed later.
Pélegry’s own exposure guidance was not fast by modern standards. For landscape work in good light, he described exposures around 10 to 12 minutes, longer when light was uncertain, and up to half an hour in shade.
7. Develop with pyrogallic acid
For development, Pélegry used pyrogallic acid with citric acid. His formula was essentially:
- Water: 100 parts
- Pyrogallic acid: 1 part
- Citric acid: 1 part
During development, he added a small amount of 3% to 4% silver solution, watched the image by transmitted light, and stopped development in water when the sky and bright parts were sufficiently dense.
This is one of the major differences from the earliest calotype methods. By Pélegry’s time, pyrogallic acid had become a major developing agent in photographic practice.
8. Fix, wash, dry, and oil
Pélegry fixed the negatives in sodium thiosulfate. His fixing bath was 75 parts sodium thiosulfate to 500 parts water, and he recommended 30 to 40 minutes of fixing, followed by washing and drying.
After fixing and drying, the negatives were still not finished. Pélegry then oiled them to reduce opacity and grain, improve transparency, and make the negative print better. He used poppy oil mixed with turpentine and allowed long soaking.
This post-oiling step connects Pélegry back to the older paper-negative tradition: the paper remains paper during the chemistry, then receives oil later to improve printing.
What Pélegry Solved
Pélegry did not replace Le Gray. He solved a different problem.
Le Gray made the waxed paper negative more practical for travel by preparing a more durable and transparent support before exposure. Pélegry kept the paper unwaxed during chemical preparation, then used careful washing, tannin preservation, dry exposure, pyrogallic development, and post-oiling.
His goal was not maximum speed. His goal was practical field use with a paper negative that could be prepared ahead, carried safely, exposed dry, developed later, and printed with the soft beauty of paper.
That makes Pélegry one of the final meaningful refinements in the paper-negative tradition.
While I appreciate what he was able to achieve, I elected not to use his workflow. I don’t personally need more than a few weeks storage life for my sensitized Le Gray calotypes, so the added complexity of Pélegry’s chemistry and workflow was not something I wanted to pursue. However, if a time in the future would come to where I need several months of shelf life for pre-sensitized calotypes, I can use his workflow because I have tested it and verified it works.
The Core Lesson
From Talbot to Pélegry, the story of the calotype is not a straight line toward sharpness or speed. It is a story of balance.
Talbot gave photography the paper negative. Furlong, Cundell, and Adamson made it more controllable. Guillot-Saguez simplified the iodizing logic. Le Gray made the process more durable, transparent, and travel-ready through waxed paper. Greenlaw showed that plain-paper methods could survive in hot climates. Pélegry gave the paper negative a late, practical form for artists and travelers who still valued paper after glass had taken over the commercial world.
That is why this history matters to my work.
The calotype is not just a primitive ancestor of modern photography. It is a different way of seeing. It accepts softness, atmosphere, paper texture, uncertainty, and handwork as part of the image.
For Pictorial Whispers, that matters deeply.
I am not trying to make photographs that look modern. I am not trying to remove the hand, the paper, or the flaws. I am trying to make images that feel like memory. The calotype gives me that. Salt printing completes it.
The chemistry matters because the chemistry shapes the emotion.
The calotype paper negative and the salt print belong together because they share the same early photographic language: paper, silver, light, time, touch, and imperfection.
That is the world I want this work to live in.
Sources
Primary source for the 1840–1852 calotype evolution: Roger Taylor and Mike Ware, “‘Pilgrims of the Sun’: The Chemical Evolution of the Calotype 1840–1852,” History of Photography, Volume 27, Number 4, Winter 2003. (Taylor & Francis)
Additional source for Pélegry: Arsène Pélegry, La photographie des peintres, des voyageurs et des touristes, Gauthier-Villars, 1879. (Internet Archive)
Wlodek Witek, “The Calotypist of Today: The Use of Arsène Pélegry Calotype Process and French Papers for a Travelling Photographer,” 2017. (Calotype 2017)
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