LightJet

LightJet is a brand of hardware used for printing digital images to photographic paper and film. LightJet printers are no longer manufactured but are however remanufactured and resold; and their lasers are still manufactured.

LightJet is a trademark of Océ Display Graphics Systems, a division of Océ N.V. (the company that acquired Cymbolic Sciences, Inc.) In 2010 Océ was acquired by Canon of Japan. The term "LightJet" is often used to generically describe a digitally made chromogenic print. Competing manufactures of equipment include ZBE Chromira and Durst Lambda.

Unexposed silver-halide (AgX) photographic paper is temporarily fixed on a stationary internal drum, where three digitally controlled lasers simultaneously expose the photo-sensitive emulsion on the paper medium (or back-lit transparency medium) with red, green and blue laser light. The amount of light from each laser varies to provide specific color and density values for each pixel imaged to the print. The light-path includes a spinning surface coated mirror mounted on an air-bearing that travels along the axis of the internal drum, thus reflecting the laser light at 90 degrees allowing for a dimensionally consistent round imaging dot across the entire area of the photographic paper. The purpose of this round imaging dot is to maintain edge to edge sharpness on the final print. The print is then processed using traditional photochemical means (usually RA4). After which, the photographic print is handled just as any other photo-print.

Whereas xerography and inkjet printing employ a halftone process and ink to reproduce digital images on paper, digital-C is a photographic continuous tone process rather than halftone or error diffusion which are common on offset press or ink-jet. The device natively supports 24-bit RGB raster files, and is capable printing vector based files when fronted by a photographic Raster Image Processor (RIP). 24 bit color continuous-tone devices use large multitudes of colors, up to 16,777,216, rather than the small number of colors available to 4-color press and 8-color ink-jet type devices. Therefore, posterization and banding are unlikely from these types of prints when provided with a file of good integrity. Due to slight halation of the light source, digital C-prints produced on high end equipment have true continuous tones not possible with images created with ink or pigments (due to CMYK halftone limitations).

...
Wikipedia