Polaroid has developed an ultrasmall printer for digital photos that provides the same instant gratification its cameras are renowned for. The printer, roughly the size of a deck of cards, can connect to a cell phone wirelessly or to a camera with a USB cable. It has hundreds of tiny, precisely controllable heating elements that draw color out of specially designed two-by-three-inch photo paper. The paper has layers of nanocrystals that turn different colors depending on how long they're heated and at what temperature.

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