The DX number was assigned by the

International Imaging Industry Association The International Imaging Industry Association (I3A) was created by a merger of the Photographic and Imaging Manufacturers Association (PIMA) and the Digital Imaging Group in 2001. It was a common forum for the industrial imaging industry. It ...

(I3A). It uniquely identifies the type and manufacturer (sensitizer) of a film emulsion. A proprietary list of DX numbers for APS and

135 film 135 film, more popularly referred to as 35 mm film or 35 mm, is a format of photographic film used for still photography. It is a film with a film gauge of loaded into a standardized type of magazine – also referred to as a casse ...

was prepared yearly or as needed. (''DX Codes for 135-Size Film'', 2004, I3A; last edition was from January 2009). The list was available for sale from the I3A.

DX number composition

A DX number has two parts separated by a dash: the "combination code" also known as "DX Number Part 1" followed by a "specifier number", or "DX Number Part 2". For example,

Agfa Perutz Agfa-Gevaert N.V. (Agfa) is a Belgian-German multinational corporation that develops, manufactures, and distributes analogue and digital imaging products, software, and systems. It has three divisions: * Agfa Graphics, which offers integrated pr ...

3-color

ISO 200/24° Film speed is the measure of a photographic film's sensitivity to light, determined by sensitometry and measured on various numerical scales, the most recent being the ISO system. A closely related ISO system is used to describe the relation ...

film is assigned 115-4 (I3A).

DX film canister barcode

For 135-film cartridges the DX number is hashed to produce a four-digit code. A suffix digit for the number of exposures and a manufacturer's proprietary prefix digit are concatenated to form a six-digit decimal code. The code is printed in

human-readable A human-readable medium or human-readable format is any encoding of data or information that can be naturally read by humans. In computing, ''human-readable'' data is often encoded as ASCII or Unicode text, rather than as binary data. In most c ...

text and also represented as an

Interleaved 2 of 5 Interleaved 2 of 5 (ITF) is a continuous two-width barcode symbology encoding digits. It is used commercially on 135 film, for ITF-14 barcodes, and on cartons of some products, while the products inside are labeled with UPC or EAN. ITF enco ...

barcode A barcode or bar code is a method of representing data in a visual, machine-readable form. Initially, barcodes represented data by varying the widths, spacings and sizes of parallel lines. These barcodes, now commonly referred to as linear or o ...

. Size and position conform to the

ANSI The American National Standards Institute (ANSI ) is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organi ...

/ NAPM IT1.14:1994 standard. To generate digits 2 through 5, the combination code is multiplied by 16 and added to the specifier number. The result is prefixed with zeroes to make four digits. For the Agfa film 115-4 above, the digits would be 1844 (16 × 115 + 4). Digit 1 is any digit from 0 to 9 and is assigned by the manufacturer. Digit 6 is a code digit for the number of full-frame exposures: 1 is for 12 exposures, 2 for 20 exposures, 3 for 24, 4 for 36, 5 for 48, 6 for 60, 0 for 72 and 7 for non-standard lengths such as 24 + 3. The barcode is located between the electrically-read silver and black

DX Camera Auto-Sensing Code DX (Digital indeX) encoding is an ANSI and I3A standard, originally introduced by Kodak in March 1983, for marking 135 and APS photographic film and film cartridges. It consists of several parts, a latent image DX film edge barcode on the film be ...

and the film cartridge exit lip. The barcode is optically scanned by many film-processing machines when the cartridge is inserted for developing (Kodak patent ''5761558'').

DX film edge barcode

Most film produced since 1983 contains a bar code at the bottom edge, which contains both the above "DX Number Part 1" and "DX Number Part 2". This information identifies manufacturers and chemistry associated with their various film types. These codes are printed on the "data track" below another bar code called a "clock track". The data track also includes a start entry pattern, frame number information, including indicating if a position is a "half-frame", a parity bit, and an exit pattern. If the manufacturer and type of film negative is unknown, a negatives' edge bar code can be examined to identify this information. Unlike the film canister DX number bar code, each frame or half-frame's data track code doesn't provide information about the total number of frames available in the roll.

References

External links

A database of DX numbers
{{DEFAULTSORT:Dx Number Photographic film markings

DX number composition

DX film canister barcode

DX film edge barcode

See also

References

Further reading

External links