Last week I began a series of posts showing you how to date your old family photographs using format and process, by looking at daguerreotypes, the very first commercial photographic process.
This week I’m going to show you how to identify a collodion positive—also known as an ambrotype—using just a few simple clues, then we’ll take a look at some examples of collodion positives in our collection.
About the collodion positive process
The collodion positive, or ambrotype, first appeared in about 1853. By the 1860s the process had largely disappeared from high street studios, but it remained popular with itinerant open-air photographers until the 1880s, because portraits could be made in a few minutes while sitters waited.
The collodion positive process, which was based on the collodion negative process invented by Frederick Scott Archer, reversed a negative image by bleaching the silver salts. The dark areas which would normally form the highlights in a printed image turned pale, and the clear areas which would form the shadows in the print appeared to be dark.
When presented against a black background, the dark areas of the original negative, which had been bleached with nitric acid or bichloride of mercury, appeared as highlights. The black backing, visible through the clear areas of the plate that originally formed the highlights, appeared as shadows.
Although the so-called collodion positive was in fact a negative, the emulsions were too thin to make satisfactory prints on paper. When a collodion positive was held to the light without the backing material, the image still looked like a negative, though paler than the standard required to make a satisfactory positive print.
The dark backing material could be a velvet pad held inside a presentation case, or a simple coating of black varnish for those made in lower-class studios and temporary booths erected at holiday resorts.
One slight drawback with this process was that the image was reversed laterally, like the reflection you see in a mirror.
To correct this, the plate could be blackened on the collodion side or presented in the case emulsion-side down, which had the added benefit of protecting the vulnerable collodion layer. Otherwise, the surface of the finished plate was coated with clear varnish and it was protected under a ‘cover-glass’.
Why is the collodion positive also known as an ‘ambrotype’?
Most people call collodion positives ‘ambrotypes’, which is technically incorrect.
The ambrotype process (patented by American photographer James Ambrose Cutting in 1854) was a particular variant of the process which used Canada balsam to seal the collodion plate to the cover glass. These are most commonly found in America.
Use these clues to identify a collodion positive
Collodion positives are often confused with daguerreotypes because they are a similar size and were also usually supplied in a protective case or frame.
They were made by taking a glass negative and backing it with black cloth, paint, or varnish to produce a positive image.
Unlike daguerreotypes, collodion positives always appear as a positive image, whatever angle you view them.
Collodion positives were much cheaper than daguerreotypes. The quality of the materials used to make their cases usually reflects this—compressed paper and card rather than leather and silk.
Examples of collodion positives in our collection
Platt D. Babbitt set up a pavilion in front of Point View, later Prospect Point, on the American side of Niagara Falls. From here he photographed tourists taking in the view, without their knowledge, from the 1850s to the 1870s. He would then offer the photographs for sale, providing a lucrative business for himself and giving tourists a chance to own a souvenir of their trip.
The sign on the cart reads: ‘Hygienic Bakery, Confectioners Co. Ltd. 7 High Rd., Willesden’. The photograph is mounted in an inexpensive papier-mâché case which was designed to hang on a wall. The subject matter, the ready-made metal mount and style of case suggest that image was taken by an itinerant or non-studio-based photographer.
The entire family appear to be rather bewildered by the process of having their photograph taken. All retain their pose, with the exception of the baby on her mother’s lap who has moved and becomes a blurry, ghost-like figure.
This British cavalry soldier is wearing a short, tight-fitting shell jacket and cap, carrying his sword and gloves in his hands. He had probably served in the British army during the Crimean War (1854–1856). This photograph has been hand-coloured to give a realistic colour to the officer’s uniform and to pick out the gold embroidery, sash and ring that he wears. Having an ambrotype hand-coloured cost extra.
The woman rests her elbow on a table, her arm next to an elegant vase of flowers and a cased photograph. The photograph on the table appears to be either an ambrotype or a daguerreotype. It may have been included to represent someone who had recently died.
These smartly-dressed, serious looking men are pictured in front of a painted background of a grand fireplace. They are all in suits and have flowers in their buttonholes, perhaps indicating this was taken on a special occasion.
More in the series
- How to spot a daguerreotype (1840s–1850s)
- How to spot a ferrotype/tintype (1855–1940s)
- How to spot a carte de visite (late 1850s–c.1910)
- How to spot a cabinet card (1866–c.1914)
- How to spot a postcard (1900–1950s)
- How to date Victorian photographs
- How to date photographs by fashion
- Researching your photographer ancestors