Works of art made from pieces of or whole natural or everyday objects. Often sheet metal is used, but many other materials are suitable. They are put together with techniques such as glueing, welding or soldering.

Bromide print
A print made using paper containing silver bromide that was sufficiently sensitive to light to be used for enlargements. Bromide papers came into general use around 1880 and became the most popular and widely used paper for black and white photography in the twentieth century. It is produced in a range of finishes: matt, glossy and semi-matt.

Contact print
A photographic image produced from a film, usually a negative. The defining characteristic of a contact print is that the photographic result is made by exposing through the film original onto a light sensitive material pressed tightly to the film. As the process produces neither enlargement nor reduction, the image on the paper print is exactly the same size as the image on the negative meaning a whole 35mm film can be viewed as one contact sheet if needed.

In many photographic processes a negative is considered a master image from which other prints are produced. A negative image is a tonal inversion of a positive image, in which light areas appear dark and vice versa. A negative colour image is additionally colour reversed, with red areas appearing cyan, greens appearing magenta and blues appearing yellow.

A photomechanical printing process for reproducing photographs in large editions invented in 1879 by Karl Klic of Vienna. Similar to an etching process, it uses a polished copper plate upon which a fine resin dust is adhered by heat. The plate is etched with acid in differing depths in proportion to the tones of the picture, the shadows being the deepest and holding the most ink. The technique was used for reproductions of the work of many of the best-known pictorial photographers in the 1890s and 1900s. Variants of photogravures include the rotogravure process used in luxury magazines from the 1910s to 1950s, and heliogravures, a process Man Ray used from 1934.

Photomontage is the process, and result, of making a composite photograph by cutting and joining a number of other photographs. The composite picture is sometimes photographed so that the final image is converted back into a seamless photographic print.

Proof print 
A print that is used for checking that an image, text, graphics and colours will come out as expected before the image is printed or published.

Silver print or gelatin silver print
Print produced on the most common form of photographic paper up to the present day, introduced into general use in the 1880s. These prints are made with silver halides suspended in a layer of gelatin on fibre based paper. They are developed using the three-bath chemistry of developer, stop, and fixer, and can be chemically toned to alter the finished look of the print.

Solarisation or Sabattier effect
An effect achieved when a photograph which has been developed, but not fixed, is exposed to light, and then continues to be developed. The resulting image has both positive and negative qualities.

Photogram or ‘Rayograph’
A photographic image made without a camera by placing objects on a sheet of photosensitised paper and exposing it to light. Man Ray’s earliest photograms date from shortly after his move to Paris in 1921, which he called ‘rayographs’, in part a play on his name.

A positive photographic image printed on a transparent base, usually glass or film, which can be viewed by light. In the 1950s Man Ray developed a technique of coating the reverse of his transparencies, which he tried to patent unsuccessfully.

Three-colour carbon transfer print  
The tri-colour carbro process involved the printing of three negatives taken through red, green and blue filters on carbon tissue that are then transferred, one after the other, onto paper to form the final print.

Vintage print
There is no uniform definition of a Vintage print but it is generally considered to be a print made close to the time at which the negative was first exposed or a print made immediately after developing a negative. Vintage prints often have a premium attached because they are considered the original piece of art. Many photographers choose to sign their vintage prints.