The ambrotype is fascinating photographic process that emerged from the use of wet collodion. It is an American invention and was patented in 1854. For those less familiar with early photographic techniques, this type can easily be confused with the daguerreotype. Especially when viewing reproductions in books or online, as the differences between the supports are harder to determine. The strikingly similar casings of ambrotypes and daguerreotypes certainly don’t make identification any easier! However, there are several distinct differences that clearly set the two apart. These differences are best observed when you have the physical object in hand. Another good reason to visit one of the many photography fairs in Europe.

The most significant difference lies in the image support. With daguerreotypes, this is a silver-plated copper plate, which literally creates a mirrored surface. The ambrotype, on the other hand, uses the collodion glass negative as the support for the image and therefore does not have a strongly reflective surface. At most, you might notice the shine of the glass.

Instead of using the glass negative to create prints, the negative itself became part of the final positive image. By providing the collodion negative with a dark background, a positive image is produced. The back of the negative was either painted black or lined with dark velvet inside the case. In the United States, there are also examples where deep dark red glass (ruby glass) was used for the backing. When viewing an ambrotype against a bright light source, it is sometimes noticeable that the dark areas in the image appear slightly deeper than the lighter parts, a phenomenon unique to the ambrotype and not seen in daguerreotypes.

As previously described, both the Anglo-Saxon world and Europe used the same type of casing for ambrotypes as for daguerreotypes. This sometimes makes identifying the technique more challenging. Japanese ambrotypes were housed in stylish kiriwood cases, often with a calligraphic inscription. Both processes also coexisted for a short period. However, since both the daguerreotype and the ambrotype were unique and non-reproducible, they eventually disappeared from the market in favour of cheaper and reproducible techniques, such as the Carte de Visite.

An interesting aspect of early photographic history is that different individuals, at roughly the same time, developed similar inventions.

In France, the daguerreotype emerged after Nicéphore Niépce and Louis Daguerre shared their experiences. Almost simultaneously, in the UK, William Henry Fox Talbot developed the calotype process. These are the two most well-known early photographic processes, yet they differ significantly in technique.

Other inventors of the same era also experimented with light-sensitive chemical compositions. However, Hippolyte Bayard’s process ultimately lost out to the daguerreotype, while Herschel’s 1842 cyanotype, with its distinct blue hue, proved too limited for commercial portrait photography.

In Great Britain, Fox Talbot had been experimenting with the light-sensitive properties of various chemical substances since 1834. A key difference from Niépce and Daguerre’s approach lay in the image support: Talbot used paper instead of a metal plate. This choice offered clear advantages over the daguerreotype. Paper was far cheaper than a silver-coated copper plate, and the paper negative allowed for multiple positive prints, which could be incorporated into publications. However, these advantages only became a genuine success later in history. The early years of photography were dominated by the success of the daguerreotype.

Fox Talbot was a scientist who lived with his family at Lacock Abbey, a magnificent country house in England. Even non-photography enthusiasts will recognise its Gothic corridors as Hogwarts from the Harry Potter films. At this beautiful location, Talbot experimented with the light-sensitive properties of silver nitrate.

As a nature lover, Fox Talbot worked with the camera lucida, an optical drawing instrument. His goal was to reproduce nature as faithfully as possible. He was, however, deeply dissatisfied with his attempts in 1833 to depict Villa Melzi in Italy. Translating reality onto paper proved far from straightforward. This frustration, however, sparked the idea of mechanically capturing an optical image. Talbot chose paper as a support for the image, a fundamental difference from Niépce and Daguerre, who favoured metal to create a printing plate. Through his experiments, Talbot discovered that salt and silver nitrate together formed the light-sensitive compound silver chloride.

During his early experiments at Lacock Abbey, Fox Talbot soaked paper in a solution of water and common table salt. Once the salted paper was dry, it could be coated with a strong silver nitrate solution. Since the light-sensitive silver chloride darkens upon exposure to daylight, a negative image was produced. Talbot’s first “photogenic drawings” were created without a camera, capturing the shadows of plants placed directly on the light-sensitive paper. The photogram was born.

Cameraless photography would continue to create turning points in history. For example, during the interwar period, modernists like Moholy-Nagy and Man Ray used the photogram to create abstract photographic prints, approaching photography as an autonomous medium. Today, cameraless AI-generated images that resemble photographs challenge us to rethink the future of the 200-year-old medium.

It was only in a later phase that Fox Talbot placed his light-sensitive paper inside a camera. The small, simple wooden cameras Fox Talbot used for his early photographic experiments were jokingly called “mousetraps” by his wife, Constance. Not for catching mice, but “to capture the sun rather than unwanted pest”.

By developing the paper negative after exposure with gallic acid, Fox Talbot achieved more workable exposure times, as the development process strengthened the latent image. From the negative, multiple positives could be created through contact printing. The result was named “calotype” and sometimes called “Talbotype”. Because the light-sensitive substance was applied directly onto the paper, a characteristic of the calotype was that the image lay between the paper fibres, producing a softer, slightly less sharp print. It is also a typical visual feature used to identify a salt print.

Working with a paper negative made it relatively easy to produce multiple prints, which were also simple to incorporate into publications, unlike the unique daguerreotype on metal.

To highlight the advantages of his invention over Daguerre’s, Fox Talbot published the photo book The Pencil of Nature in 1844. Additionally, the art magazine Art Union featured an illustrated article on the calotype in 1846, with each issue containing an original print!

However, this stunt also exposed the process’s drawbacks. The positives were significantly less sharp than daguerreotypes, a pictorial quality that would only be reappraised much later. More critically, the prints in Art Union faded quickly, dealing a severe blow to the reputation of this photographic process.

Disheartened by these setbacks, Fox Talbot lost interest in the photographic process and focused instead on photomechanical printing techniques.

When technical obstacles were overcome by fellow inventors and photographers, Fox Talbot’s negative/positive principle evolved into the foundation for the further success of photography. Working with negatives as the basis for producing positive prints would remain the standard in the photographic world until the digital revolution.

The early years of photography were marked by a rapid succession of inventions, all driven by the desire to reduce exposure times or streamline the photographic process. The use of wet collodion on glass emerged from the quest to combine the remarkable sharpness of the unique daguerreotype with the easily reproducible, but less sharp, paper negatives introduced by Talbot.

The goal of merging the best of both techniques ultimately led to the development of glass negatives. The glass negatives allowed light to pass through unimpeded, resulting in sharp prints. Negatives also have the advantage of being reproducible. Photographers were not seeking a unique process but rather a method to efficiently duplicate images. From a commercial perspective, the ability to sell the same photograph to as many customers as possible was highly appealing. After experiments with gelatin and albumen, Frederick Scott Archer introduced the solution in 1851: wet collodion on glass.

Collodion, a dilution of alcohol, gun cotton (nitrocellulose), and ether, served as the binding layer between the glass and the photographic image. Silver iodide was used as the light-sensitive silver salt. The primary challenge was that the collodion had to be processed while still wet. This meant photographers had to cast, expose, and develop the negative on-site. A portable darkroom quickly became standard equipment for every 19th-century photographer. Some photographers used compact tents as workspaces, while others, like Roger Fenton, repurposed an old wine cart to serve as a mobile photo lab.

Of course, these negatives were merely an intermediate step toward the positive prints that customers took home. They served as a working tool for photographers, who could now build their own archives. Preserving the negatives was profitable, as it allowed for reorders, something impossible with unique processes like the daguerreotype or ambrotype.

Vintage collodion glass negatives are certainly worth studying. They offer insight into the working methods of 19th-century photographers. The example accompanying this article clearly shows the collodion at the edges. Often, fingerprints in the corners or streaks from the pouring process are visible. The image tone is typically brown with a milky appearance. The four nearly identical portraits in the example were taken with a CDV camera. This type of camera had multiple lenses to produce several smaller copies in a single exposure, creating Cartes de Visite. This way, the customer could quickly obtain multiple photos, while the photographer only had to prepare the glass plate once. Defenitely a practical win-win situation!

Positive prints from glass negatives were typically made on albumen paper, the standard for most of the 19th century.

The very first photographic process that was commercially available is the daguerreotype. It is a truly fascinating and aesthetic object.

The writer Oliver Wendell Holmes describes this new invention by Louis Daguerre and Nicéphore Niépce from 1839 very aptly and poetically: a mirror with a memory.

The negative and mirrored image becomes positive and clearly visible via a black reflection. Finding the right viewing angle requires some experience and searching. But the reward is great when it succeeds. A razor-sharp image!

Instead of casting a fleeting glance, viewing a daguerreotype requires more time and interaction with the photo itself. It becomes a conscious act and a personal viewing experience. Very different from what we have become accustomed to digitally today.

Producing such a razor-sharp image does require some preparation by the photographer. A first step is carefully polishing the silver-plated copper plate into a reflective surface. The more refined this was done, the better the image quality. The plate is made light-sensitive in a small wooden box using iodine vapours. Silver iodide is formed during this phase.

In the early days, exposure times of a few minutes to half an hour were required. These long exposure times are beautifully immortalised in the famous photograph Daguerre took of the Boulevard du Temple. The busy street in Paris appears deserted, except for a “lonely” shoe shiner with a customer. Gradually, the exposure time could be reduced to a few seconds. This technical advancement made it possible to create portraits as well, thereby promoting the success of the technique among the general public.

To make the latent image visible, to develop it, mercury vapours are used. The formation of a silver-mercury amalgam creates the image. The still light-sensitive parts are neutralised in the next step by fixing the daguerreotype. Initially with table salt, and later with hypo or sodium thiosulfate. Rinsing with water and drying are the final steps. Because the image is exposed directly onto the plate via the camera, without the intermediate step of a negative, the photograph is mirrored and unique.

To protect this fragile image on the daguerreotype, the photographer fitted the copper plate with a case. Naturally, this also served an aesthetic purpose. In this way, the unique photograph becomes an object to be cherished.

The origin of a daguerreotype can often be deduced from the style of the casing. For instance, there is a difference between European and Anglo-Saxon presentations. European photographers made a cardboard cassette with a passe-partout and a glass cover. In the US and UK, a case that could be closed was more commonly used. This case is a small wooden box covered with leather or paper. Variations made of thermoplastic material with opulent motifs also exist.

Another indication of the daguerreotype's origin is the silver mark. Due to the use of casings, this detail is usually not visible. However, with a loose plate or during restoration, this silver mark can provide information about the manufacturer of the silver-plated copper plate.

Because it was not yet possible to photograph in colour, there are examples of beautifully coloured daguerreotypes. The French erotic stereotypes were coloured manually with great care and realism. In other examples, only a jewel has been touched up or colour added to the cheeks. The skills of the photographer and the extra price the client has to pay certainly influenced the result.

If a vintage daguerreotype still has the original glass, it is advisable to store the object with the image facing down. Otherwise, glass corrosion could cause irreparable damage. Due to the fragility of daguerreotypes and the complexity of the casing, it is recommended to leave any restoration to professionals.

The fact that this invention had a major impact on the 19th-century population is beautifully depicted in a caricature by Maurisset: La Daguerréotypomanie. A procession of enthusiasts queues up to have their portraits taken or walks around with large sliding box cameras under their arms. Amidst other industrial inventions of the 19th century, such as the steam train, the sun looks on smiling and approvingly at all the enthusiasts “writing with light” using this new invention, the daguerreotype.

A macabre detail is the bodies of engravers dangling from rented gallows. There were certainly people who feared for their jobs due to the new invention. With AI, we realize all too well that a new technology can shake everything up considerably. Just as with the invention of photography, well-known systems will change and some will disappear. But just like back then, there are opportunities associated with it as well. We are experiencing the photographic history of tomorrow today!

And perhaps it is precisely this extensive digitisation that will once again lead to greater appreciation for unique objects such as the daguerreotype.

The technical principle behind creating a tintype (also called ferrotype) closely resembles that of the ambrotype. Both techniques use wet collodion as a binding agent and a black background to produce a positive image. The primary difference lies in the support material: photographers used inexpensive tinplate for tintypes, while ambrotypes rely on glass as their base.

Adolphe Alexandre Martin, a French photographer, is often credited as the inventor of the tintype process. He experimented with collodion on metal plates in the early 1850s. However, American inventor Hamilton L. Smith patented the ferrotype process in the United States on February 19, 1856. Peter Neff was also a pioneer in this field. Interestingly, as with many photographic processes, multiple inventors independently developed similar techniques.

A thin metal plate is first blackened, often using Japan lacquer. Next, wet collodion is carefully poured over the entire plate, creating a thin adhesive layer for the photographic image. The tintype is then immersed in a silver nitrate solution, forming light-sensitive silver salts. Like all collodion processes, photographers had to process everything while the plate was still wet. This necessity led to the use of portable darkrooms, which were essential for fieldwork.

Once the plate is light-sensitive, it is exposed in the camera. Even with this technique, exposure times were several seconds long, making instant snapshots impossible. Studios commonly used posing aids to help subjects remain still during exposure.

After exposure, the latent image is developed using an iron (II) sulphate solution. Following development, the image must be fixed to remove unexposed silver salts and prevent further light sensitivity. For this, sodium thiosulphate (commonly known as hypo) is used.

Although the entire process required considerable skills and precision, travelling photographers visited carnivals and annual fairs using this technique. Having a portrait taken became an event. In order to work and serve customers even more smoothly, photographers worked with cameras that had multiple lenses. In this way, several images could be obtained simultaneously during one exposure time. More for the same price and effort, a commercial trick that still works today. After exposure, the plate was cut into individual pieces so each photograph could be given to the customer separately, typically mounted in a simple paper mat. Unfortunately, many of these mats have been lost over time.

The use of inexpensive materials and multi-lens cameras made portrait photography far more accessible. As a result, posing styles also became slightly more informal.

Tintypes, or ferrotypes, are characterised by visible collodion edges and often clearly visible cut edges. When a tintype is framed, it can be difficult to distinguish from an ambrotype. A small magnet can provide clarity: tinplate is magnetic, while glass is not.

It is not a rare photographic process in itself. But because it was more accessible than other techniques, there are real gems to discover for enthusiasts and collectors of vernacular photography.