Photography has been around for a long period of time, and despite the many different early photographic processes, perhaps 3 main ones stood out: Daguerreotype, Ambrotype, and Tintypes. In particular, ambrotype is one of the many early photographic processes used to develop and “print” photographs.
The ambrotype process is documented to have been created by James Anson Cutting in 1854 however, it is stated that the process was actually first used by Frederick Scott Archer 3 years prior to Cutting, to create some of the first few portraits of this method. Before ambrotype, another process known as daguerreotype was very popular. Ambrotype had easily overtaken daguerreotype in popularity and usage as soon as it came out mainly because it was easier to view and cheaper to produce. The main reason for this was because unlike daguerreotype, ambrotype did not have a surface that is mirror-like or shiny which made viewers have to tilt the photo to a certain angle to be able to see the image. Ambrotype was also cheaper to produce and required a shorter exposure time in order to capture an image. Ambrotype are basically positive photographs that has been exposed onto glass, or to be more precise, “iodized collodion and silver nitrate on glass”.
Nevertheless, it must be noted that the glass itself when the image is produced is actually negative. However, as it is often placed against a dark background, the image appears positive. To put it simply, ambrotype was a glass plate that was covered with collodion that contained iodide, and then put into a silver nitrate solution, making it so that the glass is sensitive to light and able to be exposed to produce an image; the glass must still be wet in order to work. To develop the image, the glass must be developed in a solution that contains “nitric acid and iron sulphate” and then bathed in either sodium thiosulphate or potassium cyanide. The glass will then be dried. With that, a negative image is actually produced or printed.
Even after drying, oftentimes a transparent varnish is used. As the last step of printing, a dark background is placed with the glass to create a positive image. In fact, the dark background sometimes create a certain depth within the image.