In 1845 - 1846, Christian Frederick Schönbein discovered nitrated cotton (guncotton) by commingling cotton fibers in a mixture of sulfuric and nitric acids. Ironically, in 1847, a young medical student in Boston by the name of John Parker Maynard formulated a durable, skin like, medical dressing from the guncotton called collodion that could be used to treat wounds from Schönbein’s explosives. In 1850, Gustave Le Gray proposed the idea that Parker’s collodion solution could be applied to photographic purposes because it was the near-perfect vehicle for holding a light-sensitive solution on glass. Shortly after, in March 1851, Frederick Scott Archer described an application of salted collodion on sheets of glass for the purpose of making glass plate negatives. Archer detailed a process where potassium iodide was combined with a solution of diluted collodion, applied to a glass plate, which was then immersed in a silver nitrate bath resulting in a light-sensitive layer of silver iodide. This sensitized glass plate was exposed in a camera immediately after being withdrawn from the silver nitrate, developed in a solution of pyrogallic acid, and fixed in sodium thiosulfate. The advantages were immediately evident. The process provided a sharp and reproducible glass negative and was far more sensitive, especially in the wet state, permitting exposure times in seconds rather than minutes. This exposure speed allowed the subject of a portrait to exhibit a bit of candid behavior. It was also democratically priced, being a fraction of the cost of the Daguerreotype. Incidentally, shortly after Archer published his experiments, enterprising photographers realized that an underexposed wet collodion negative, when laid on a dark background and viewed in reflective light, would appear as a positive. This visual phenomenon led directly to the even more democratically available Ambrotype and tintype processes.

The technique of making a tintype was elementary. The process was essentially like an Ambrotype but executed on a thin sheet of lead  (not tin) that was pre-coated with a smooth “skin” of asphaltum. The blackened lead sheet was then coated with collodion and sensitized immediately before exposure as in Archer’s wet collodion process. The plate was then exposed in a camera that had a slotted bottom that led to receptacles holding processing chemistry. Then the plate was washed in a bucket of water and air-dried. The images were referred to as “little gems” and cost less than twenty-five cents apiece. The metal tintype was more durable than a glass Ambrotype and eliminated the need for a negative-to-paper sequence because the positive image illusion was made in-camera. It was the first instance where an ordinary person could participate in the new medium without benefit of a scientific education or an abundance of free capital.

Although the image quality left something to be desired, the tintype was extremely popular, especially during the period between 1860 and 1880, and used extensively by itinerant and holiday location photographers. The tintype was significantly faster than any process that had preceded it and that fact allowed subjects to be more personal and candid with their poses. Its ability to provide a sturdy, although reversed, image of the sitter, while that sitter waited for the results, made it the people’s process of choice (much to the dismay of the fancy commercial studios) until the introduction of George Eastman’s dry plate in the 1880s.