Photographic Terms*

Albumen printing paper was introduced by Louis-Désiré Blanquart-Evard in May 1850, and remained in general use until about 1895.  It could be bought partly prepared, i.e. coated with a thin film of white of egg and was then sensitized with silver nitrate solution by the photographer.  Toning with chloride of gold checked fading and produced a sepia effect, avoiding the unattractive reddening to which the paper was prone.

Cabinet photography was a standard size of photograph and almost always a portrait.  Replacing the carte-de-visite, it was popular from mid-1860s to 1900.

Calotype, also known as a Talbotype, was pantented  in 1841 by William Fox Talbot.
It allowed multiple prints to be taken from a single negative.  The calotype negative was a fine writing paper coated with a solution of silver nitrate and potassium iodide, which was dried and brushed with solutions of silver nitrate and gallic acid.  The negative was developed in a solution of gallo-nitrate of silver, rinsed and fixed.  The whole process had to be carried out on the same day.  The negative was then waxed, for the sake of translucency and to reduce printing time.

Daguerreotype was the first commercial photographic process.  It was made public by Louis-Jacques-Mandé Daguerre in 1839.  Daguerreotypes were unique images fixed on silver-coated copper plates.  The silvered surface was treated with iodine and bromine vapours, to create a light-sensitive halide.  After an exposure of several minutes’ (15-20 minutes in the beginning) duration in a camera, the plate was developed over a dish of heated mercury, to bring out the latent image, which was then fixed in a bath of sodium thiosulfate.  Daguerreotypes were reversed images, thus as ‘positives,’ they could not be multiplied.  They also had to be protected by a glass cover to prevent oxidation and abrasion. The wet-collodion process replaced the Dageurreotypes in the 1850s.

Film negatives were first introduced around 1886.  It was a sensitized gelatin emulsion backed by paper which was quite fragile and soaked off during processing.  In  the 1890s cellulose nitrate grew in popularity as a film base.

Fixing is the process of making an image permanent by washing away unaffected silver halides using hypo.  The image is thus made insensitive to further exposure to light.

Hypo = abbreviation for hyposulfite = sodium thiosulfate

Salted-paper print was announced by Fox Talbot in 1839.  In this process, light-sensitive salts were soaked into the paper, which was then sensitized with silver nitrate and exposed to daylight under a negative, with the two held together in a printing frame. Susceptible to fading, originally the paper and negative were held together until an image of sufficient density was produced; then the paper was washed and the image fixed.

Wet-collodion process, announced by Frederick Scott Archer in 1851, surpassed all other processes by 1850.  Collodion is gun cotton dissolved in ether, which creates a membrane transparent to the touch, to which is added potassium iodide.  The mixture was spread on a glass plate and then sensitized in a bath of nitrate of silver and exposed in a camera while still moist. Exposures were from ten seconds to one and half minutes. Plates had to be developed immediately after exposure with either pyrogallic acid or ferrous sulphate and then fixed with sodium thiosulfate or potassium cyanide.  Traveling photographers who used this process needed to take with them a dark tent and developing outfit.  Wet-collodion remained in use till 1880, despite the invention of a dry-collodion process in the 1850s, when it was replaced by a gelatin dry-plate process.

*Information found and edited from: “The Photo Book,” Phiadon