Digital wet laser minilabs work in the following way: The paper is pulled from a light-tight "magazine" containing a roll of paper and cut into sheets. After cutting an inkjet printer marks each sheet with up to 80 characters of information spread over 2 lines, before exposure using a scanning and modulated set of red, green and blue laser beams. After exposure by lasers, the paper passes through tanks, one containing a developer, the next a bleach/fixing agent (which may also be separate) and the next containing filtered rinsing water followed by tanks with conditioning chemicals, before being dried with hot air, ejected and sorted. The chemicals are automatically mixed from a cardboard box containing the necessary chemicals in separate bottles. The minilab contains filters and heaters for the chemicals, and it discards used chemicals into a separate, single bottle. Minilabs may contain 2 or 4 magazines, each with a paper roll of different width. The laser beams are scanned across the paper using a rotating mirror octagon driven by a stepper motor. Each full rotation of the octagon exposes 8 lines on the paper. Sensors are used to synchronize the rotation of the octagon with the signals sent by the AOM drivers to modulate the lasers. The lasers and AOMs are inside a dust-tight enclosure. Dust outside the output window of the enclosure can affect image quality. The lasers may be heated and their temperature monitored.