See Albumen process. Printing paper invented by Louis Désiré Blanquart-Evrard in 1850. Paper coated with albumen (white of egg) and light-sensitive material. The paper was placed in a frame with the negative for contact printing in the sun, exposure time varying from a few minutes to hours. As a printing-out paper, albumen prints produced an image upon exposure to the sun, without need for chemical development. The resulting image was bathed in gold chloride to produce a rich brownish tone (if dried in sunlight the brown turned dark gray). This paper was eventually mass-produced, making sensitized paper readily available to the amateur. A chief disadvantage was their impermanence.
A process discovered by Abel Niepce de Saint-Victor and announced in 1848. Albumen (white of egg) was used as a medium to carry the light-sensitive material and produce a negative on glass. It was known for its fine detail. The usual exposure time of 5 to 15 minutes was reduced if the plate was exposed while wet, necessitating the availability of a dark area and chemicals for the travelling photographer. The Albumen process was not as popular as the collodion process.
A process discovered by Frederick Scott Archer and Peter W. Fry in 1852 and published in 1854. A collodion glass negative was bleached, causing the darkened areas to appear as a white metallic silver. A positive appeared by placing the image against a dark background, such as black velvet or dark varnish, and using reflected light from the silver. The result is very similar to a daguerreotype, but without the brilliant mirror-effect. In America, James Ambrose Cutting patented the process and Marcus A. Root coined the term `ambrotype.'
The adjustable opening in a lense that allows a determined amount of light to pass through.
A printing-out paper made from collodio-chloride of silver nitrate emulsion paper. The advantage over albumen paper was that it was more sensitive and permanent. Introduced by George Wharton Simpson in 1864, it was manufactured in Munich in 1867. The name "Aristotype" was coined in Düsseldorf by Raphael Eduard Liesegang. Like the albumen print, Aristo prints were commonly toned with gold chloride and burnished to a high gloss.
A color process perfected by the Lumière brothers (Louis and Auguste) in France in 1907. A photographic plate was covered with starch grains dyed with orange, green and violet. The blank spaces were filled with black powder and then the entire plate was coated with a light-sensitive emulsion. The plate was exposed through the back and then made into a positive with a reversal process. The result was a full color transparency.
Joseph Nicéphore Niépce's process of making a heliographic copy of an engraving, discovered in 1822. It was the first photomechanical technique of reproduction. A process in which an oiled engraving (to allow light through) was placed on top of a glass or pewter plate prepared with bitumen of Judea. The bitumen exposed to light became hard, while the bitumen under the printed lines of the engraving remained soft. The soft bitumen was washed away with a solvent. The result was a permanent copy of the engraving which could then be etched and printed. Niépce also used this process for making direct positives on metal and glass plates.
See albumen prints.
A type of commercial photograph introduced in England in 1866. A print 5½ x 4" mounted on cardboard 6½ x 4½". They were particularly popular as publicity photographs for actors and well-known figures. Napoleon Sarony was one of the most prominent practitioners.
Fox Talbot's process patented in 1841. An early process of paper photography where paper sensitized by potassium iodide and silver nitrate (forming silver iodide) was washed with a mixture of gallic acid and silver nitrate and exposed in a camera. It was then developed in the same solution of gallic acid and silver nitrate. The first negative/positive process was developed by contact printing the paper negative onto silver chloride printing-out paper. Also called Talbotype.
A glass prism used to show the operator the subject and his drawing paper at the same time, thus enabling him to draw what is before him with precision. It was first designed by William Hyde Wollaston in 1807.
A darkened room or box in which objects from outside are projected on the opposing wall through a pin hole. The phenomenon was noted by Aristotle. It is a forerunner of the modern photographic camera.
The first practical method for printing a permanent image. It was conceived by Alphonse Louis Poitevin in 1855. Powdered carbon was mixed with bichromated gelatin (or a similar substance) and spread on paper. The paper was exposed under a negative. The carbon hardened and remained in proportion to how much light it received. Unexposed carbon was washed away creating a positive image. The half tones were later improved by Sir Joseph Wilson Swan, who introduced the use of carbon tissue in 1864. The outcome was a permanent image with a rich tonal scale.
A type of paper print pasted on cardboard measuring 4 x 2½". It was patented by André Adolphe Eugène Disdéri in 1854 (although several claim invention). The most important innovation was Disdéri's camera which could take eight poses on one large negative, allowing a single print to be cut into eight separate images. Quick and efficient, it is the earliest instance of mass-production portraiture.
Etienne Jules Marey's method of capturing a moving figure with a sequence of exposures on the same plate (introduced c. 1882). Marey used a photographic gun with a rotating slit shutter to accomplish these images.
A small circle of light formed by a lens or pin hole as it projects an image. Clusters of light rays form tiny circles (known as circles of confusion) to make up an image; if the circles are large, they will overlap with others, forming a blurred image. If the circles of confusion are small, the image will be sharp. A very small pinhole or a lens helps keep these circles small and the image sharp.
A popular process whereby glass plates were sensitized with an emulsion of collodion containing potassium iodide dipped in silver nitrate and exposed while still wet. It was introduced by Frederick Scott Archer in 1851. The most important disadvantages to the process were that the exposure had to be taken while the plate was still moist and developing had to be done very soon after exposing. For this reason, it was often called the "wet-plate process." Its high sensitivity (a small portrait could be taken in 2 to 20 seconds) made it an extremely popular process until the 1880s. See also ambrotype.
A method of photomechanical reproduction patented in 1855 by Alphonse Poitevin. Material (stone, metal, glass, etc.) is coated with bichromated gelatine, exposed under a negative and moistened with water. The result is that the material accepts ink in proportion to the amount of light it receives. Prints can be drawn straight from the gelatine surface. Many variations of the process appeared under the names of photolithography, albertype, heliotype, phototypie and Lichtdruck.
Printing more than one negative, or one negative several times, on a single sheet of paper or light- sensitive material
Producing a print by placing the negative in direct contact with the paper or other sensitized material. The resulting image is the same size as the negative.
Paper prints produced by the albumen negative. John A. Whipple and the Langenheims (Frederick and William) coined the term `crystallotype" in the United States. Whipple would continue to use this name for prints he obtained from collodion negatives.
Considered the origin of practical photography, announced by Louis Daguerre in 1839. A copper plate was coated with highly polished silver. The silver was sensitized by vapor of iodine, which formed a layer of silver iodide on the surface. After the plate was exposed to light in a camera, it was developed by heated mercury vapor. The mercury attached itself to those areas affected by light, which were then fixed with common salt and washed and dried. The positive was created by reflecting darkness from the polished silver, not the mercury which formed a white amalgam. The mercury was easily scratched and so the daguerreotype was framed behind glass and the edges sealed to prevent oxidation of the silver. The disadvantages were that the image was hard to see (due to the need for reflection); the picture was laterally reversed because it was a direct positive; and there was only one image, it could not be used as a negative.
The process in which exposed film or paper is chemically treated to make the latent image appear and remain in a relatively permanent state. More specifically, the step, before fixing, in which film or paper is bathed in a chemical that produces the initial image.
An instrument used to project and make a photographic image larger, or sometimes smaller, than the negative. Although Alexander Wolcott patented an enlarger to rephotograph daguerreotypes on a larger plate in 1843, it was not until the late 1850s that the forerunner of the present day enlarger came into use.
The focal length of a lens divided by the diameter of the aperture. It is used to determine depth of field as well as the amount of light allowed to the film.
A similar process to the Ambrotype; however, instead of using a glass negative with a dark background a sheet of iron, japanned black, was coated with a light-sensitive material and exposed. The process was introduced by Frenchman Adolphe Alexander Martin in 1853 and patented in America in 1856 by Hamilton Smith. Also called tintypes and Melainotypes.
The material commonly used in a camera to record an exposure. Today, it usually consists of transparent acetate or plastic supporting the light-sensitive material.
A chemical solution that makes a photographic image insensitive to further exposure to light. It generally dissolves unexposed silver halide crystals. The most prevalent fixers are sodium thiosulfate or ammonium thiosulfate. Sometimes called hypo.
When the lens is focused on infinity, the distance from the optical center of the lens to the plane on which the image is focused (focal plane).
The photographic technique that uses a protein obtained from animal tissue and hooves (gelatin) as a medium to hold light-sensitive silver halide crystals in an emulsion. Although many experimented, the technique is generally attributed to Dr. Richard Leach Maddox, who published his experiments in 1871. The most important innovation which led to present day dry techniques was accomplished by John Burgess and by Richard Kennett in 1873. By 1882 the dry gelatin process had superseded the collodion wet plate. Its chief advantages were the ease of handling ready-made dry plates and shorter exposure times than the wet collodion plate. This process led to a new wave of amateurs toward the end of the nineteenth century. Along with negatives, gelatin printing paper came into use about the same time. Most modern day processes are based upon the gelatin technique.
A process that became popular in 1894 with the work of Robert Demachy and Alfred Maskell. Gum arabic mixed with potassium bichromate changes its solubility in water in proportion to its exposure to light. Photographers would wash a sheet of paper with a mixture of gum solution and watercolor pigment and expose it to light beneath a negative. When washed in water the pigment would disappear in proportion to the amount of light to which it was exposed. A popular process at the turn of the century, photographers would mix sawdust and other materials with the gum and develop the print with a brush to give it a painterly appearance.
A color process discovered by Louis Ducos du Hauron and Charles Cros individually in 1869. A subtractive color process based on the fact that white light contains all the colors. Negatives taken through red, blue and green filters are printed as positives on cyan, yellow and magenta transparencies. Each color absorbs its own compliment. The transparencies are then placed in register to form a full color image.
Literally "sun drawing," the name Nicéphore Niépce gave to his early experiments in photography in 1827. At first reproducing an engraving and then the image in a camera obscura, Niépce captured an image with a plate sensitized with bitumen of Judea and developed with a mixture of oil of lavender and white petroleum.
See collotype.
See fixing bath.
The invisible image produced on sensitized material when it is exposed to light. Chemical developing makes the image visible.
See tintype.
A photographic image which has the opposite tones of the original subject. Generally, the film exposed in a camera and developed to produce an image.
A technique used by Fox Talbot possibly as early as 1833. A paper negative is produced by placing objects on paper sensitized with silver nitrate and salt and exposing it to the sun. The paper darkens according to the amount of light it receives. Talbot fixed his early images with a solution of salt or potassium iodide.
A photographic image made by placing objects on sensitized film or paper and exposing it using a moving or stationary light source. The image is made without the use of a camera.
(From the Greek light and to write). The term suggested by Sir John F. W. Herschel in 1839 for Fox Talbot's process (see calotype). It was adopted as a general term for subsequent processes.
A photomechanical process of reproduction invented by Karl Kli_ in 1879. Sensitized carbon tissue was exposed through a positive transparency. The gelatin on the tissue became hard in proportion to the amount of light it received. The tissue was then squeezed onto a bitumen-coated copper plate and the paper base was pulled away, leaving only the hardened gelatin on the plate (highlights had more gelatin and shadows had less). The copper plate was then etched with ferric chloride, biting into the metal in proportion to the amount of gelatin (more in the shadows and less in the highlights). The etched plate could then be inked and printed. The advantage of the process was the subtle tonal values. Peter Henry Emerson was so impressed with the quality that he made his own photogravures and called them original photographs, not reproductions.
A composite image made by combining several parts of photographs or several photographs.
A print process patented in England in 1873 by William Willis and sold commercially by the Platinotype Company in 1879. Platinum and iron salts, light sensitive and more stable than silver, were used for making extremely permanent prints. The subtle half-tones and soft grays made this process extremely popular among artistic photographers.
see Platinotype.
Hand-drawn lithographic copies of daguerreotypes produced by John Plumbe in the mid 1840s. Plumbe was a successful American daguerreotypist from 1840 to 1847.
A photographic image with tones corresponding to those of the subject. See negative.
Sensitized paper that produces a visible image when exposed to light, without the need for chemical development.
See photogram.
The phenomenon which occurs when paper or film is exposed to light during development. The technique, sometimes called solarization, causes a partial reversal of tones.
Silver chloride printing-out paper created by soaking paper in a salt solution and brushing it with a silver nitrate solution.
See photogram.
A common light-sensitive component of photographic emulsions. It is composed of silver chloride, silver bromide and silver iodide.
(Abbreviated SLR) a camera in which the image formed by the lens is reflected from a mirror to ground glass for viewing. When exposure is taken the mirror is mechanically removed so the light can reach the film.
See fixing bath.
See Sabbatier effect.
Two images paired side by side that, when viewed individually by each eye (through a stereoscope), produce the illusion of three dimensions.
See stereograph.
See calotype.
See Ferrotype.
The technique of photographing devised by Alvin Langdon Coburn around 1915. Abstract images were created by placing three mirrors together (facing one another) and photographing through the triangular prism created. Ezra Pound, a member of the Vorticism group of English painters, suggested the name vortoscope for the instrument and vortograph for the image.
See collodion process.
A photomechanical printing process patented in 1864 by Walter Bentley Woodbury. The images are noted for their continuous half-tones which are often difficult to differentiate from true photographs. A negative was printed on sensitized gelatin (creating a gelatin positive) and impressed upon lead under tremendous pressure. Warm pigmented gelatin was poured onto this intaglio mold. A piece of paper was then hand pressed to create the print. Impressed gelatin created the image and was then hardened in alum bath.
An invention announced by W. G. Horner in 1833 and named in 1867. An open drum with slits in its side was placed on a spindle so it could revolve. Drawings on the opposite wall were viewed in succession as if the image were one and moving.
Created by Eadweard Muybridge in 1880, the first instrument to show projected photographs in succession. Muybridge demonstrated persistence of vision and helped pave the way for what would become cinematography.