Collodion Process

The collodion process emerged as a transformative photographic technique during the mid-nineteenth century, enabling the production of highly detailed grayscale images on glass or metal plates. Known chiefly as the wet-plate process, it required rapid preparation and development and therefore influenced the working practices, equipment, and artistic possibilities available to early photographers. Its invention and refinement marked a significant transitional moment between the earlier daguerreotype and calotype processes and the later adoption of gelatin dry plates that defined modern photography.

Origins and Development

The theoretical foundations of the collodion process were first outlined in 1850 by the French photographer Gustave Le Gray, although his formulation was not immediately practicable. The effective and widely adopted version was created by Frederick Scott Archer, who developed the method in 1848 and published it in 1851. His innovation rapidly gained attention due to its combination of fine image detail and reproducibility, qualities that placed it between the one-off daguerreotype and the paper-negative calotype.
During the 1850s and 1860s, the process was refined by numerous photographers and chemists who experimented with variations in chemical composition, plate preparation, and exposure conditions. By the end of the 1860s, the collodion wet plate had become the dominant photographic medium, largely replacing the daguerreotype in commercial portraiture and artistic work.
A major shift occurred in the 1870s with the introduction of the gelatin dry plate by Richard Leach Maddox in 1871. These plates were far more sensitive to light and could be stored before use, eliminating the need for a portable darkroom and dramatically shortening exposure times. As a result, gelatin dry plates superseded collodion for most professional and scientific applications.

Principles and Technical Characteristics

Collodion, a viscous solution made from nitrocellulose dissolved in ether and alcohol, served as a vehicle for holding light-sensitive silver salts on the plate surface. In standard wet-plate practice, the glass or metal plate had to be coated, sensitised in a silver nitrate bath, exposed in the camera, and developed—all within approximately fifteen minutes. This requirement made the process labour-intensive and logistically demanding, especially outside the studio.
Although collodion could be used in a dry form, drying significantly reduced its sensitivity, resulting in exposure times that could exceed thirty minutes. Consequently, dry collodion was used mainly for landscape photography, where long exposures were more acceptable.
The process was uniquely selective in its light sensitivity, responding chiefly to blue and ultraviolet wavelengths. This resulted in characteristic tonal distortions: warm colours such as red or yellow registered very dark, foliage appeared pale, and skies often lacked detail unless supplemented with separate exposures.

Advantages of the Collodion Method

The collodion process offered substantial benefits over earlier methods and contributed to its rapid adoption:

• Reproducible negatives: When applied to glass, the process produced a stable negative from which many paper prints could be made, unlike the single-image daguerreotype.
• Fine image detail: The smooth glass support allowed for exceptional clarity, surpassing the graininess of paper negatives.
• Lower cost: Materials were relatively inexpensive, and preparation did not require the hazardous fuming procedures associated with daguerreotypes.
• Shorter exposure times: Under daylight, exposures of only a few seconds were typical, enabling more practical portraiture and reducing motion blur.

These advantages made collodion the favoured medium for commercial studios, documentary work, and scientific illustration throughout the mid-nineteenth century.

Limitations and Practical Challenges

Despite its strengths, the collodion process presented significant difficulties:

• Strict timing: Plates had to remain wet throughout coating, exposure, and development, limiting the usable window to around ten to fifteen minutes.
• Portable darkrooms: Photographers working outdoors required tents, wagons, or portable chambers to prepare and process plates on site.
• Chemical instability: Sensitising baths deteriorated over time, accumulating impurities that caused inconsistencies and failures in plate development.
• Handling hazards: Silver nitrate caused permanent staining and posed explosion risks when residue accumulated in equipment.
• Spectral limitations: The blue-only sensitivity distorted colours and made subjects such as clouded skies difficult to capture.

These challenges motivated extensive experimentation aimed at producing a reliable dry-collodion alternative.

Search for a Dry Collodion Process

Throughout the mid-nineteenth century, many chemists and photographers attempted to create a workable dry-plate variant of collodion. Well-known investigators such as Joseph Sidebotham, Richard Kennett, Major Russell and Frederick Charles Luther Wratten tested various additives—including albumen, tannic acid, magnesium nitrate and glycerin—to slow evaporation and preserve sensitivity.
Although these adhesives prolonged dampness, none yielded a method that matched the consistency, sensitivity or convenience of later gelatin emulsions. Consequently, dry collodion remained a specialist technique rather than a mainstream solution.

Applications in Nineteenth-Century Photography

Wet-plate collodion was used across a wide range of genres:

• Portraiture: Commercial studios adopted ambrotypes and tintypes, which provided affordable, sharp likenesses.
• Landscape and architectural photography: Detailed images could be produced on large plates, reflecting the era’s growing interest in topographic documentation.
• Scientific and industrial uses: Its clarity and reproducibility made it suitable for technical illustrations and printed materials.

One of the most remarkable achievements of collodion photography occurred in Sydney, Australia, in 1875. Photographer Charles Bayliss, assisted and funded by Bernhardt Holtermann, created some of the largest known glass-plate negatives of the nineteenth century. Plates measuring up to 160 × 95 cm produced sweeping panoramas of Sydney Harbour from a tower built specifically for this purpose. Several of these historic plates are now held by the State Library of New South Wales.

Survival and Revival in the Modern Era

While the collodion process was largely replaced by gelatin silver technology in the 1870s, certain forms—such as tintype portraiture—remained in occasional use into the early twentieth century. Within the printing industry, collodion survived into the 1960s for specific line-and-tone reproduction tasks due to its low cost and high contrast.
In the twenty-first century, the wet-plate process has experienced a notable artistic revival. Contemporary practitioners value its handcrafted aesthetic, its unpredictable imperfections and the tactile presence of its plates. Photographers produce ambrotypes and tintypes at historical reenactments, arts festivals and gallery exhibitions. Workshops, manuals and modern reproduction equipment support a growing international community of collodion artists.
Modern photographers continue to explore the medium’s creative potential. Some artists undertake residencies to document natural environments using nineteenth-century techniques, producing bodies of work celebrated for their atmospheric and distinctive visual qualities. Annual events such as World Wet Plate Day bring together practitioners who maintain the tradition and share evolving interpretations of the historic process.