Since the beginning of photography there have been many photographic processes. Some of them remain to this day, some crashed and burned within two decades of their release even if the quality of the resulting image using that process what pristine. It's safe to say economics and practicality had a lot to do with it.
The daguerreotype was the first photographic process made available to the public. It was announced in Paris, in 1839 and involved a process in which a silvered metal plate was exposed to iodine fumes, forming a light-sensitive surface of silver iodide. The plate was then exposed to fumes of mercury and the photograph developed in a salt solution. The reason for it’s eventual demise was the fact each photograph could only be produced once which opened the doors for the negative-positive processes that allowed for unlimited copies.
The above photo is of Andrew Jackson in his late 70s in either 1844 or 1845, a year before his death, not too long after the daguerreotype was revealed.
The cyanotype/blue-print is one of the longest surviving photographic processes. Invented in 1840 by Sir John Herschel, it involved a mixture of ferric ammonium citrate and potassium ferricyanide used to produce a light sensitive paper. It was relatively simple in administering as it required no development or fixing. What it did involve was “washing”. Amateurs in the nineteenth century, architects (hence “blue-prints”), and engineers fancied this photographic process.
The above photo is of visually impaired artist John Dugdale titled “Self Portrait with Long Hair” done in 1995.
Waxed Calotype Negative
Patented in 1841 the calotype process was the first practical negative-positive photographic process. The process involved a sheet of quality paper being treated with light-sensitive silver compounds and then exposed inside the camera. The image was developed in gallo-nitrate of silver. The negative-positive process is the basis of modern photographic practice. Digital imagery is now challenging this. Photographers often applied heated wax to the developed negative to increase printing transparency and hide the fine fibers found in the paper.
The Scottish portrait and historical painter Thomas Duncan is pictured in this calotype, taken in 1844.
Salted Paper Print
The process involved soaking quality paper in a salt solution and then proceeding to brush it with a solution of silver nitrate to produce light-sensitive silver chloride. The sensitised paper/negative was then exposed to sunlight which resulted in an image that was then fixed and toned. Though, we today appreciate the sharpness of an image the softness of the salted paper print was prized by early photographers.
American businessman Cyrus W. Field is pictured above in 1858, the year in which he laid the first telegraph cable across the Atlantic Ocean.
Wet collodion negative
Introduced in 1851 and by the end of that decade it had almost entirely replaced the first practical photographic process, the daguerreotype. It remained the standard form of photography from onset till the early 1880s. The preparation process of the glass negative for exposure involved the sheet of glass being coated with a solution of iodised collodion and then made light-sensitive by immersion in a bath of silver nitrate. The glass negative required sensitising and exposing while chemicals were still damp which is why it was known as a “wet process”.
The above deteriorated wet plate shows Theodore Roosevelt, another American President.
Announced in 1850, the Albumen, named after the fact egg white was used in sealing the paper. It was the most widespread medium between 1850 and 1890. The surface layer of the mix of albumen and salt made the photo much more dense, giving it a sharpness that the salted paper print didn’t have. What’s more is that the fixed print could be toned to create a wide variety of colours.
First patented by A. L. Poitevin in 1855, the carbon print process involved realizing that gelatin mixed with an alkaline bichromate becomes insoluble when exposed to light. It was brilliantly thought that Carbon as well as other pigments could be used as to obtain a range of tones and colors in the final image.
The above portrait is of the poet Charles Baudelaire taken in the 1860s.
This intaglio printmaking/photo-mechanical process involves coating a copper plate with a light-sensitive gelatin tissue, exposing it to a film positive image, and then etching to highlight the shadows of the original. What you got was a printing plate to use for replications.
The beautiful image above is of the contemplative Victor Hugo in 1883.
Information for this article was taken from The British Library