The desire to see a finished photograph immediately, without tedious and time-consuming processing, is as old as photography itself. The earliest ‘instant’ process was the ferrotype or tintype, invented in 1852 by A. A. Martin and used for well over a century afterwards, especially by itinerant street and seaside photographers.
Like the tintype, traditional photo booths used conventional processing, speeded up by means of high concentrations and temperatures. A digital photo booth uses digital capture, then writes the image either to conventional silver halide paper or (less often) to some other printing medium such as dye sublimation. To a certain extent, too, some types of digital photography may be regarded as ‘instant’, especially those where the camera can be docked directly with a printer (normally dye sublimation) which produces a small print quickly and without further intervention.
Since 1947, however, ‘instant’ photography has been all but synonymous with the Polaroid Land camera, invented by Edwin Land. This has effectively gone through two generations, the original peel-apart type (which survives for many applications) and the integral type.
The peel-apart variety was first demonstrated on 21 February 1947 at the American Optical Society; the first Polaroid camera, the Model 95, went on sale in a Boston department store on 26 November 1948. The technology is an ingenious combination of conventional and novel techniques. The exposure is made on a negative material, which is then brought into close contact with the positive material, with the developing agent sandwiched between the two. The developing agent is viscous, and is typically contained within a pod that bursts when the sandwich is drawn through two rollers. The really clever part is that the unused silver in the negative image diffuses across to the positive material to create the final image; the original images were sepia, but black-and-white arrived in 1950. Polacolor (1963) refines this technology, using a dye-diffusion process to create a colour image. After development, the two halves of the sandwich are peeled apart; the negative is either discarded or (with some types of black-and-white film such as Type 55 P/N, introduced in 1961) cleared with sodium sulphite, washed, and dried.
As well as the obvious applications for snapshots, identity photographs, and professional testing of exposure and lighting, the colour films in particular have attracted considerable attention for their ‘fine-art’ potential. (A few art photographers, such as Toto Frima, have used Polaroids almost exclusively; many others, and the British painter David Hockney, have had significant Polaroid phases.) The two most usual techniques are emulsion transfer and emulsion lift. In the former, the materials are separated before development is complete, and the image is rubbed down onto another support; in the latter, the image is floated off the finished print and caught on another support. Watercolour paper is popular as the support in both cases.
There have been several formats, some short-lived, some enduring; there are also giant peel-apart cameras, generally up to 508 × 610 mm (20 × 24 in), but these are rare and extremely expensive to run.
Emulsion types have also come and gone, such as Type 413 infrared (introduced 1964).
The same peel-apart technology has also been applied to transparencies, both monochrome and additive colour: Polachrome (1983) transparencies are made up of a grid of coloured lines, rather along the lines of some early colour processes. This was also the basis of the short-lived Polaroid movie process. Like all additive colour systems, the transparencies are dark as compared with additive films, and Polaroid reversal films are also particularly tender and prone to scratching. Those who use them for their (considerable) creative potential normally either duplicate them onto conventional reversal materials, or scan them, rather than entrusting them to the tender mercies of origination houses.
Because peel-apart films use a highly modified version of conventional processing, both time and temperature are important: the higher the processing temperature, the shorter the processing times. Below about 18 °C, 65 °F, processing may be so slow that it effectively never finishes.
Integral films first appeared in 1972 with the SX-70. A grey film is ejected from the camera, and develops before the user's eyes. The chemistry here is a good deal cleverer even than the peel-apart variety, with a vanishing opacifier and the ‘pod’ chemistry described above remaining in the image as a new stratum between other strata in the film. Development is always to completion, so time and temperature are much less important.
Again, there have been quite a few formats. The appeal of these films has generally been to amateurs; they find limited use in technical and scientific work, and there has been some creative interest in the way in which the image can be manipulated by physical pressure on the film as it is developing.
Because Polaroid cameras produce big images in camera, the cameras themselves need to be big: depth of field is shallow, and focusing must be precise. Polaroid devised numerous ingenious solutions to the problems involved, including ‘folding’ the light path with mirrors; sonar autofocus; and ultra-fast materials (to allow the use of small apertures for maximum depth of field).
Most attempts to produce similar materials to Polaroid (whether peel-apart or integral) foundered either on patent violations or on the sheer ingenuity of Polaroid's scientists in coming up with ever-better materials. The only enduring rival, with a much smaller range of materials and sizes, has been Fuji. And yet, in the early 21st century, the Polaroid corporation ran into serious financial difficulties, a victim principally of digital photography, which replaced many Polaroid applications where speed was more important than quality.
— Roger W. Hicks
Bibliography
- Hockney's Photographs, introd. M. Haworth-Booth (1983).
- Hitchcock, B., and Klochko, D. (eds.), Innovation/Imagination: Fifty Years of Polaroid Photography (1999)
