Contact printing is a method of producing a photographic print from a negative. In the dark, or under a safelight, the printer places an exposed and developed piece of photographic film, emulsion side down, on a piece of photographic paper, briefly shines light on the negative, then develops the paper into a print. The print that results is a contact print.
Because the light does not pass through air or lenses in going from the negative to the print, the contact process can preserve all the detail that is present in the negative. Photographers also prize the beautiful gradation that results from making prints in this way. However, the print is only the same size as the image on the negative. This makes contact prints from large-format negatives, especially 5x7 and larger sizes, most feasible for fine-art work. Smaller contact prints, from films and formats such as 135 film cassettes (35 mm) and 120/220 rollfilm (6 cm), are useful for evaluation of exposure, composition, and subject qualities; the photographer then prints selected negatives using an enlarger.
Contactprints are used to produce proof sheets from entire rolls of 35mm negative (from 135 film cassettes), and 120 (2 1/4 film rolls, to aid in the selection of images for further enlargement, and to aid in cataloging and identification.
In medium and Large_format photography, contactprints are prized for their extreme fidelity to the negative, with exquisite detail that may be seen with the use of a magnifying glass.
Contactprinting was also used at one time in photolithography and in printed circuit manufacturing.
Offset printing was used for the fabrication of capacitors [7] and printed and plated metal lines as narrow as 25 µm [8].
Printing speeds varied between 0.1 and 10 mm/s, and applied forces were adjusted between 0.5 and 10 N. The width of the contact zone between the stamp and the substrate was approximately 2 mm, leading to maximum pressures of 40 kPa.
During a printing step, an ink may be transferred to the substrate (additive print) or removed from the substrate (subtractive print), the chemical nature of the substrate may be altered in the zones of contact (convertive print), or the substrate itself may be selectively removed (etching).
Feeds |
Contact