| Transparency (photography) |
Article Index for Transparency |
Information AboutTransparency (photography) |
|
In Photography , a transparency is a still, positive image created on a Transparent base using photochemical means. The terms '''slide''' and '''reversal film''' are also used. Contrast with Negative and Print . HISTORY The earliest practical Color Photography was the Autochrome process. This was an additive 'screen-plate' method which produced a colour slide, but was fairly dim, and with the colour resolution limited by the fineness of the screen-plate. The earliest practical method using a 'subtractive' method was the Kodachrome process, which produced much brighter color transparencies. Originally used mainly for news Reportage , it gradually gained wider popularity. As a medium for serious amateur photographers, it gained popularity as an alternative to black and white print film starting in about 1945 .Some amateurs were using Kodachrome for family snapshots as early as 1940 with many utilizing 35 mm roll film adaptors with common 4″×5″ "press cameras." At this time, color print film had many shortcomings including high cost of film and processing and short print life. Amateurs who could afford slide film and projection equipment used it extensively until about 1970 , when color print film began to displace it. Through about 1995 , color transparencies were the only photographic medium used for serious publishing, and were widely used in commercial and Advertising photography, reportage, sports, stock, and nature photography. Digital media have since gradually replaced transparencies in many of these applications. The use of slides for artists submitting to juried shows or applying for solo exhibitions, applying to Art School s or for residencies (or the like), however, is still nearly universal for a number of reasons, among which is the actual or perceived lack of colour Fidelity in Digital Media . CHARACTERISTICS Slides are still generally preferred by professionals and many amateurs when working with traditional film. Slides are often sharper and have better colour reproduction. Generally slides have a longer life span than colour prints. Kodachrome is well known for its Archival qualities. Color does not fade in Kodachrome for a long time. Theoretically they should last about 200 years compared to perhaps 50-70 years for negative colour-film processes (e.g. Kodacolor or Afgacolor) and 20-30 years for colour prints. The Kodachrome process uses toxic and difficult to control chemicals in the development process and so remains in use in only a few locations worldwide. Direct positive slide film is less forgiving of Exposure errors than the negative - print - and development process chain. With negatives, the overall value may be sensed after processing and the exposure of the positive image controlled to compensate. The simplest Point And Shoot and Disposable Camera s do not even control exposure, a demonstration of the wide ''exposure latitude'' of the processes. It is also more cumbersome to display if only a few images are to be shown, although small battery powered direct viewers are available and suitable for use by one or two viewers. A slide is a special type of transparency intended to be projected onto a screen using a Slide Projector . This allows the photograph to be viewed by a room-full of people at the same time. Slides were at one time an important media for presentations, but LCD Projector s which are now widely available have largely replaced traditional slide projectors for this purpose. The most common form of modern slide is the 35mm Slide , essentially a positive-image printing onto the standard 35mm Film used in the Movie industry, then placed inside a cardboard or plastic shell. Older projectors used a sliding mechanism to manually pull the transparency out of the side of the machine, where it could be replaced by the next image, and it is from this that we get the name "slide". Modern projectors typically use a ''carousel'' that holds a large number of slides, and viewed by a mechanism that automatically pulls a single slide out of the carousel and places it in front of the lamp. Transparency film, in sizes ranging from 35mm roll film up to 8x10" sheet film, are produced by Kodak , Agfa , Konica , Scotch, and Fujifilm . Essentially all film sold today uses either the E-6 Process or the K-22 Process , with the overwhelming majority using the E-6 process. Polaroid produced an Instant slide film called Polachrome . It was packaged in cassettes like normal 35mm film. A separate processing unit was used to develop it. BLACK AND WHITE Black and white transparencies can be made directly with many types of Black-and-white film using '' Reversal-processing ''. It was once popular for presentation of lecture materials using 4 " by 5" glass mount slides. Such positive black and white projection is now rarely done, except in motion pictures. Even that is quite rare, except for technical uses like high-speed photography and is done by taking a positive print of the original negative, processed normally, rather than by reversal-processing the original film. In the cinema black and white is used largely to reproduce a '' Film Noir '' appearance. SEE ALSO |
|
|