Dye Diffusion Print

Manufacturing

As with the majority of photographic techniques, the principle behind instant photography involves the combination of a negative and a positive. The receiving paper, which becomes the positive, is pressed against the negative by two rollers inside the camera. As the positive and the negative pass through these rollers, a pod breaks open, releasing the reagent product, which spreads between the negative and the positive. The image is then formed from a complex diffusion and transfer process. For black and white films, unexposed photosensitive salts are transferred from the negative to the positive. For colour films, dyes are transferred from one layer to another. A final chemical reaction sets the image so that it can then be viewed in direct daylight after one minute. There are two different types of film: detachable (peel apart) film and integral film. In the first case, after exposure, the photographer pulls the film out of the camera. After a minute or so, the negative is manually separated from the positive and then is either disposed of or fixed with a pencil dipped in fixative so that it can be preserved. In the case of integral films, used from 1972 onwards, the photography is directly ejected from the camera. There is no additional manual step and no more production of waste soaked with chemicals, as the negative sheet forms an integral part of the final print. One of the advantages of the integral films it is a “clean” process that no longer gets the photographer’s hands dirty and makes it easier for amateurs to use.

Instant developing also allows alternatives uses of the process, such as emulsion transfer, in which the image layer is separated from its initial substrate in a bath of warm water and then placed on a new substrate, such as paper, metal or fabric. The dyes could even be transferred directly to a new type of paper, such as watercolour paper.

Identification

Instant picture prints can be used for other processes too, such as for the transfer of emulsion, where the image layer is separated from the initial support in a bath of warm water and then placed on a new support, such paper, metal or tissue. The dyes could even be transferred directly to a new type of paper, such as watercolour paper.

In 2007, the Polaroid company announced that it would no longer be producing film for instant cameras. In 2008, however, Florian Kaps, creator of the website polaroid.com, in collaboration with Ilford and with the help of former Polaroid employees, set up the Impossible Project and successfully re-launched production. This lead to new instant films appearing on the market in 2010.

Identification

Polaroid® are easily recognizable by their glossy, plastic-coated aspect and their standard, wide white borders. The SX 70’s amateur format measures 3,5 x 4,5 inches (9 x 11,5 cm); other professional formats include 4 x 5 inches (10 x 12.5 cm) and 8 x 10 inches (18x25 cm). A large-format (“mammoth”) camera measuring 20x24 inches (41x60 cm) was manufactured by Polaroid® for the production of artistic photographs.

Deterioration

High temperatures significantly accelerate the deterioration of the dyes used in colour photographs, as well as that of the paper, adhesives and plastics. Prolonged exposure to light can cause irreversible colour changes and a reduction in contrast or, typically in the case of Polaroid® photographs, severe yellowing of the whites in the image. In the event of very low or fluctuating relative humidity, the delicate image layer of Polaroid® photographs from a certain period may crack. Other forms of deterioration are possible depending on the different types of Polaroid® film or other brands of instant film (delamination, oxidation of the image with the appearance of spots).

Glossary