DX number

The last edition of the list, entitled DX Codes for 135-Size Film, was published in January 2009.

Some film-processing machines optically scan the barcode when the cartridge is inserted for developing.

The data track consists of:[4][5]: §6 This information identifies manufacturers and chemistry associated with their various film types.

If the manufacturer and type of film negative is unknown, the data track can be examined to identify this information.

The frame number and half-frame indicator are extensions to the original data track, added by Kodak in 1990.