Polaroid (polarizer) Polaroid (polarizer) Polaroid is a type of synthetic plastic sheet which is used as a polarizer or polarizing filter. A trademark of the Polaroid Corporation, the term has since entered common use. The original material, patented in 1929 and further developed in 1932 by Edwin H. Land, consists of many microscopic crystals of iodoquinine sulphate (herapathite) embedded in a transparent nitrocellulose polymer film. The needle-like crystals are aligned during manufacture of the film by stretching or by applying electric or magnetic fields. With the crystals aligned, the sheet is dichroic: it tends to absorb light which is polarized parallel to
Instant camera integral instant film, similar to but incompatible with Polaroid's SX-70 film. The film was chemically similar to Polaroid's with the exception that the negative was exposed from the rear and the dye/developers diffused to the front of the photogragh. This alleviated the need for a mirror to reverse the image before it struck the negative. Even so, Polaroid brought a patent-infringement lawsuit against Kodak, and eventually Kodak was forced to stop manufacture of both the camera and film. Kodak was also left to pay a settlement to customers who were left without a way to use their now defunct cameras.