Film
The process, invented by Polaroid founder Edwin Land, was to employ diffusion transfer to move the dyes from the negative to the positive via a reagent. A negative sheet was exposed inside the camera, then lined up with a positive sheet and squeezed through a set of rollers which spread a reagent between the two layers, creating a developing film sandwich. The negative developed quickly, after which some of the unexposed silver halide grains (and the latent image it contained) were solubilized by the reagent and transferred by diffusion from the negative to the positive. After a minute, the back of the camera was opened and the negative peeled away to reveal the print.
In 1963, Land introduced Polacolor pack film, which made instant color photographs possible. This process involved pulling two tabs from the camera, the second which pulled the film sandwich through the rollers to develop out of the camera. The instant colour process is much more complex, involving a negative which contains three layers of emulsion sensitive to blue, green, and red. Underneath each layer are dye developing molecules in their complementary colours of yellow, magenta, and cyan. When light strikes an emulsion layer, it blocks the complementary dye below it. For instance, when blue strikes the blue sensitive emulsion layer, it blocks the yellow dye, but allows the magenta and cyan dyes to transfer to the positive, which combine to create blue. When green and red (yellow) strikes their respective layers, it blocks the complementary dyes of magenta and cyan below them, allowing only yellow dye to transfer to the positive.
In 1972, integral film was introduced which did not require the user to time the development or peel apart the negative from the positive. This process was similar to polacolor film with added timing and receiving layers. The film itself integrates all the layers to expose, develop, and fix the photo into a plastic envelope commonly associated with a Polaroid photo. The SX-70 camera was the first to utilize this film.
Improvements in SX-70 film led to the higher speed 600 series film, then to different formats such as 500 series (captiva), and spectra.
Read more about this topic: Land Camera
Famous quotes containing the word film:
“Lay not that flattering unction to your soul,
That not your trespass but my madness speaks;
It will but skin and film the ulcerous place,
Whilst rank corruption, mining all within,
Infects unseen.”
—William Shakespeare (1564–1616)
“Television does not dominate or insist, as movies do. It is not sensational, but taken for granted. Insistence would destroy it, for its message is so dire that it relies on being the background drone that counters silence. For most of us, it is something turned on and off as we would the light. It is a service, not a luxury or a thing of choice.”
—David Thomson, U.S. film historian. America in the Dark: The Impact of Hollywood Films on American Culture, ch. 8, William Morrow (1977)
“If you want to tell the untold stories, if you want to give voice to the voiceless, you’ve got to find a language. Which goes for film as well as prose, for documentary as well as autobiography. Use the wrong language, and you’re dumb and blind.”
—Salman Rushdie (b. 1948)