and other original & alternative processes for developing images

“daguerreotype of Edgar Allen Poe”

Photography went through various stages of development as a science and an art form. No one person or country can boast the “invention of photography” but rather collections of scientists and artists from all over the world are responsible for the various processes developed.

Images were first transferred to photographic plates (made of tin, iron, platinum, silver and gold) but each print was individual and very costly.

Other processes were developed to increase the commercial success by using paper or albumen (egg white) to create more than a single image.

Johann Heinrich Schulze in 1727, discovered that silver nitrate darkened upon exposure to light

Thomas Wedgwood and Sir Humphry Davy, early in the 19th cent., created what we now call photograms

Photographic plates are flat sheets of metal or glass on which a photographic images can be recorded

Photographic plates preceded the development of photographic film as a means of photography

These plates used light-sensitive emulsion of silver salts discovered by Schulze

The French physicist, Joseph Nicéphore Niepce, made the first negative (on paper) in 1816

Unable to draw well, Niépce first placed engravings, made transparent, onto engraving stones or glass plates coated with a light-sensitive varnish of his own composition

He then created the first known photograph (on metal) in 1826 – he called these heliographs

Louis Daguerre was a French artist and inventor of the daguerreotype process. He is famous for obtaining positive photographic prints.

He invented the photographic process, in 1839, in which a picture made on a silver surface sensitized with iodine was developed by exposure to mercury vapor.

the ambrotype process is a photographic process that creates a positive photographic image on a sheet of glass using the wet plate collodion process

the ambrotype, is simply an underexposed glass plate negative and when placed against a dark background, it appears as a positive image.

it was patented in 1854 by James Ambrose Cutting of Boston, in the United States

the ferrotype, also called the melainotype or tintype, was America's first major contribution to the art of photography

To put a glossy surface on (a print) by pressing, while wet, on a metal sheet (ferrotype tin).

a positive photograph made on a sensitized sheet of enameled iron or tin - a thin piece of black enameled, or japanned, iron was used as opposed to glass

William Henry (called Fox) Talbot in 1841, created the calotype which is a positive contact print in sunlight

called the Talbotype the base of a calotype negative,

rather than the glass or film to which we have become accustomed, was high quality writing paper

under near-total darkness, the sensitive calotype paper was loaded in the camera

a composition sensitive to some or all of the actinic rays of light, consisting of one or more of the silver halides suspended in gelatin, applied in a thin layer to one surface of a film or the like

mixture of two or more liquids in which one is dispersed in the other as microscopic or ultramicroscopic droplets (a colloid)

emulsions are stabilized by agents (emulsifiers)

Treat a surface with an agent: originally a piece of highly polished silver or glass, later the use of emulsions allowed for paper

Place a negative on the surface & expose to light (UV light works best) Remove the negative and run the image through various chemicals Continue the chemical processes and remove agents Develop the image, let dry, and then for later processes, different metals or papers

were used to increase reproduction of the image

a photographic picture obtained by the use of a cyanide developed by Sir John Herschel in 1842

Herschel had the fortune to be around just at the time both Daguerre and Fox Talbot were announcing their discoveries

He was evidently very smitten by the Daguerreotype

Coined the terms photography, snapshot and negative/positive in this context

Another invention of Sir John Herschel, it is a photographic picture taken upon paper prepared by the use of a sensitive salt of iron and developed by the application of chloride of gold

He coated a sheet of paper with a ferric citrate and exposed the paper to the sun in contact with an etching that presumably had been made semi transparent

Iron Silver Processes Kallitypes and Vandykes are similar, both

being iron-silver processes Vandyke prints are simpler to produce and

require less processing Kallitypes on the other hand are more

complicated to make but offer much greater latitude in contrast and image color

small albumen prints mounted on cards 2-1/2 by 4 inches - were wildly popular and made for decades in countries around the world

the standard format was patented by a Parisian photographer, Andre Adolphe Disderi, in 1854

is a way of making photographic reproductions without the use of silver halides

the process used salts of dichromate in common with a number of other related processes such as sun printing

a contact negative the same size of the finished print is then placed on top of the dried coating and exposed to an ultraviolet light source, typically bright sunshine