DX Cartridge Barcode
Next to the film exit lip is an Interleaved 2 of 5 barcode and a printed number which represent the I3A assigned DX number, the number of exposures and a proprietary manufacturer's code. The DX number identifies the manufacturer, film type, and by inference, the necessary developing process type. This is used by automatic photo-finishing machines to correctly process the exposed film. (Kodak US patent 4965628)
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