| Everything You Ever Wanted to Know About Your Family Photographs | |
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Another advance in photographic history was the use of gold toning. In this process, the silver image was partially converted to gold by treatment in a solution containing gold chloride. This process was first applied to paper prints in 1847. It changed the image tone on a silver paper from reddish-brown to purple and significantly improved the stability of the silver image. Most prints that are in excellent condition today, are that way because they have been toned.
Ambrotypes
In 1851, Frederick Scott Archer announced his wet plate collodion process.
Collodion is celluose nitrate (or cotton) dissolved in ether and alcohol. In
order to provide the most sensitive film (fastest), the plate had to be exposed
while still wet, hence its name. This system provided a transparent negative and
although through other methods this negative image could be made positive (as in
the ambrotype), its most significant contribution was the use as a transparent
negative. The use of the wet-plate negatives to produce positive images on
albumen paper truly altered the course of photography, but the most popular use
of this was the ambrotype. By backing the collodion negative with a dark
material the image appeared as a positive. In some examples, dark purple, blue
or red glass was used as a support, thus eliminating the need for a backing.
Ambrotypes were presented in mounts and cases in the same fashion as
daguerreotypes and because of this they are commonly mistake for daguerreotypes.
It is a simple matter to distinguish between the two since ambrotypes appear as
positives at all angles of viewing as opposed to the daguerreotype which is
truly visible as a positive only at certain lighting angles.
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| Left photo is what you would see under normal viewing conditions. The right photo is what you would see if you were to shine light through the Ambrotype. | |
Ambrotypes were
most popular from 1851-1880.
Tintypes
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| Example of tintype with format being 2 1/2" x 3 1/2" also called 1/6 plate. |
The idea of using a thin sheet of iron with a surface coated with a black varnish as a support instead of glass with a dark backing was patented by Hamilton Smith in 1856. This process would be more properly called ferrotype, since there is no tin in it at all. This expensive and easily handled form of photography was a particular favorite of traveling photographers from the time of its introduction in 1854 to as late as the 1930's. They were made in the millions and are very commonly found today. America was the favorite place of production. Early tintypes were cased like daguerreotypes and ambrotypes. It is very difficult to tell an ambrotype from a tintype when it is under glass in a case. Uncased tintypes are readily identified by the thin metallic plate holding the positive image. Occasionally tintypes are found on plates that are brown or red instead of black. Most tintypes were varnished to protect the surface from abrasion and atmospheric attack. They were made in a variety of sizes from the most common format being 2½ x 3½ inches, the same size as the carte de visite paper prints.
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Images © 2000 David Mishkin. All Rights Reserved.
