DX encoding: Difference between revisions

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==DX film edge barcode==

[[Image:Dx-film-edge-barcode.jpg|thumb|DX film edge barcode]]

Below the sprockets under each frame of 135 film is the DX film edge barcode. The barcode is invisible until the film has been developed. It is optically imprinted as a latent image during manufacturing. The barcode is used by photo finishers to identify each frame for printing. It consists of two parallel linear barcodes, one for a synchronizing clock, and the other encoding film data such as type, manufacturer and frame number.<ref name="Kodak_4965628"/> The barcode nearest the film edge (away from the sprocket holes) contains the encodingencoded film data. The encodingencoded film data repeating sequence begins with 6 start bits, followed by 7 bits of DX Number Part 1, 1 unassigned bit, 4 bits of DX Number Part 2, a 9-bit frame/half-frame number, and finishes with 4 stop bits.<ref>{{Cite journal|last=Gschwind|first=Rudolf|last2=Zbinden|first2=Erwin|last3=Trumpy|first3=Giorgio|last4=Delaney|first4=John|date=2017|title=Color negatives at the demise of silver halides|url=https://doi.org/10.5167/uzh-142330|journal=ICOM-CC 18th Triennial Conference Preprints, Copenhagen, 4–8 September 2017|volume=|pages=188-191|via=[[University of Zurich]]}}</ref>

Some image processing software utilized by [[Film scanner|film scanners]] allow selection of film manufacturer and type to provide automatic color correction. Interpreting the DX film edge barcode may provide this information, permitting accurate color correction to be applied.