History of photography. Diamond post card Gun.

 Yesterday I visited the historical-archaeological Museum in Tatarstan and saw an interesting exhibit.

 This is a rare issue of the magazine "Nature and people" in 1914. I noticed an interesting ad that promises serious income: "Earn money with diamond post card gun. The greatest invention of the century. Taking pictures without the negativity for a minute." This gum is made in Metal&Ferro Co Chicago USA
 Here it is - the ancestor of the Polaroid, I thought. I am very much interested. Started to search in Russian Google, but no mention about the greatest invention of the twentieth century I have not found. The given search result in the English language. First came across an advertisement in the magazine "Popular Mechanics":
 And after another 5 minutes, finally found a modern photo of this miracle gun for postcards.

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 It turns out it's ferrotype - method of capturing photographic images that do not require laboratory processing of the picture. As the cards were used a thin metal plate coated with a photosensitive layer of collodion, which allowed to directly obtain a positive image. Ready the stood out almost instantly. Sometimes ferrotype additionally painted and framed in a passe-partout. The disadvantages of the technology have been quite serious. The picture quality left much to be desired and did not differ in high definition and over time the photographs could appear rust. Here is an example of ferrotype, or otherwise - tintype:

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 This type of photographic technique became widespread in the United States after the civil war. In Europe and Russia, it was used much less frequently. Already in 50-th years of the twentieth century, the traditional system of negative-positive printing is almost completely replaced ferrotype. Of course, the technology used to this day in the systems of instant analog photography, including the Polaroid is completely different. Still, thanks to instantaneous production of the image, it can be considered as the progenitor of the Polaroid. Polaroid is now experiencing a rebirth, and it deserves a separate story.

Alexey