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
Polaroid Swinger correctly. Earlier models also displayed the word "NO" when not properly adjusted, while later units used only the YES indicator. The Swinger also included a built-in flashgun for AG-1 flashbulbs. The Swinger used Polaroid's 20-Series roll film, which was the first Polaroid roll film to develop outside the camera. Variants included the Model M-15 "Swinger Sentinel" (the Swinger II in non-US markets), which was a cheaper Swinger without the built-in flash, and the Model 3000 "Big Swinger", which used 100-Series pack film instead of the old-style picture rolls. The Swinger name was also used on several international-market Polaroid cameras in