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Photo Friskets

Aerial photographs are usually marked with a strip of data along one edge, known as a frisket. This feature explains the standard format for such strips and explains how to read and understand them.
Individual photo frame numbers are normally recorded automatically in the film chamber, and appear in one corner of the photograph as a three- or four-digit number. However, this alone is not enough to identify any given photograph since frame 4003, for example, will appear in most films numbered from 4000 onwards. A frisket giving the unique sortie, or mission, reference as well as other important details relevant to the mission is therefore added during printing. In modern Western military photography, the information contained in the frisket conforms to NATO STANAG 3189, the standard NATO format for labelling aerial imagery. The title strip above is an example of this standard and translates as:
Frame number (029), camera position (starboard-facing, depressed at 15 degrees from horizontal), the unit (VAP-62, Detachment 19), the service (US Navy), film and sortie number (219/206), date (26 July 1963), time (09.46am, GMT), camera focal length (24 inches), flying height (2,000 feet), general area photographed (Annan), the authority for the mission (Commander-in-Chief US Naval Forces Europe, 1963), the security classification (Secret) and any caveats (US and UK personnel only).
Modern British military imagery is referenced by a sortie number, which begins with the unit or squadron designator. In the Second World War, alpha-numeric sortie references were issued by the Central Interpretation Unit at RAF Medmenham and allocated to films delivered from strategic photographic reconnaissance units. Some examples of these appear below.


Frame: 0662

Sortie: T/0560

Unit: No.1 Photographic Reconnaissance Unit, Royal Air Force (1PRU)

Date: 8 September 1941

Camera focal length: 28-inches

This is the right-hand camera in a split-pair, with an arrow showing the direction of flight




Frame: 2008

Sortie: FNO/0189

Unit: No.8 Operational Training Unit, Royal Air Force (8OTU)

Date: 13 October 1942

Camera focal length: 14-inches




Frame: 4063

Sortie: 106G/2474

Unit: 542 Squadron, Royal Air Force (part of 106 Group, RAF)

Date: 26 August 1944

Camera focal length: 36-inches




Tactical reconnaissance units allocated sortie numbers by prefixing them with their unit or squadron number, in a similar fashion to those that would become familiar to NATO units during the Cold War.


Frame: 4121

Sortie: 16/1926

Unit: 16 Squadron, Royal Air Force

Date/Time: 23 March 1945

Camera focal length: 36-inches

Aircraft altitude: 25,000 feet




Frame: 0010

Sortie: MON/0072

Unit: Escadrille de Reconnaissance 4/33, French Air Force (FAF 4/33)

Date/Time: 4 November 1956 at 10.35am GMT

Camera focal length: 6-inches

Aircraft altitude: 100 feet

Classification: Secret






NATO STANAG 3189 - Standard for Titling Air Reconnaissance, Air Survey and Air Mapping Imagery


Frame Number: Each individual frame is numbered in numerical order from 0001


Camera Position:

  • V - Vertical. If more than one camera is used, cameras are numbered from nose to tail, e.g V1, V2
  • F - Fan. The letter F is followed by two digits, the first to indicate the number of cameras in the fan, the second being the camera number, e.g F43, F44
  • P - Port. A port-facing oblique camera
  • S - Starboard. A starboard-facing oblique camera
  • N - Nose. A forward-facing oblique camera
  • PFFO - Port Forward-Facing Oblique camera (now designated N1)
  • SFFO - Starboard Forward-Facing Oblique camera (now designated N2)
  • T - Tail. An aft-facing camera


Squadron Number and Detachment letter, where applicable, e.g 58A


Service: RAF, USAF, RCAF, etc


Sortie Number: If more than one film is exposed in any camera during a sortie, the sortie number is followed by a part number, e.g. Pt1, Pt2


Date Time Group: in the format DDTTTTZMMMYY format, where Z represents the relevant time zone, e.g 301300ZJUL68


Focal Length: The focal length of the lens in inches or metric measure. 


Designation: A letter code describing the type of photography, such as:

  • N - Night
  • R - Infra-red
  • C - Cartographic survey


Flying Height: The height of the aircraft in feet above mean sea level. 


Security Classification: The permitted distribution of the imagery.





In the commercial aerial survey sector, each company labels its output in its own way, but it is normal for film references to feature a combination of company abbreviation, year and job number.


Modern aerial survey cameras record flight data on the film, by imaging various instruments when the shutter is released. This data appears along one edge of the frame in 'bubbles' recording the camera type and focal length, the altitude of the aircraft and the time of day. An additional bubble shows a spirit level, allowing photogrammetrists to calculate the amount and direction of tilt of the aircraft at the moment of photography. An example of this appears below.



Frame: 0010

Sortie: MER/160/71

Unit: Meridian Airmaps Limited

Date/Time: 25 October 1971 at 12.39pm GMT

Camera focal length: 152.05mm

Aircraft altitude: 8400 feet




Frame: 5570

Sortie: HSL/UK/86/0100

Unit: Hunting Surveys Limited