Processing
Unlike 135 film, processed (developed) APS film is stored in the original cartridge. For identification, every roll of APS film has a six-digit ID code on the label, which is also stored magnetically and is visible on either end of the processed negative. This ID is usually printed on the back of every individual print. This ID was designed to be an additional convenience both for the photoprocessor (who can easily match each strip of processed film with its cartridge, and each cartridge to a particular customer's order) and for the consumer, who can easily locate the correct cartridge if reprints are desired.
To facilitate automatic processing of film, a unique DX number is assigned to the different types of film.
APS film is typically processed by using a small machine to transfer the exposed APS film from the original cartridge to a reloadable one, then re-attached to the original cartridge and rewound using another machine after processing.
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