The photograph reached the newspapers around the world only after passing through a gauntlet of human decisions and technical difficulties. The technology used to produce and transmit the photograph appears antique today. 

Nick Ut's eight rolls of Kodak 400 ASA black and white films were developed in the lab of the Saigon AP office by the Japanese photographer ' Ishizaki Jackson', a known AP Tokyo news photographer at this time. The development solutions (Ilford Microfen developer and self-mixed fixative) were stored in large food jars. Since the temperatures of the chemicals were rarely below 30 degree centigrade the processing time was relatively short and the film had to be slowly moved at all times, by hand, like slow-motion laundering. The films were then dried in a special cabinet with hairdryers rigged up and switched in a way as not to damage could the swelling emulsion. 

Nick and Ishizaki prepared a selection of eight 5x7 inch prints for the next "radio photo cast" at 5 PM - but an editor at the AP rejected the photo of Kim Phuc running down the road without clothing because it showed frontal nudity. Pictures of nudes of all ages and sexes, and especially frontal views were an absolute no-no at the Associated Press in 1972. While the argument went on in the AP bureau, writer Peter Arnett and Horst Faas, then head of the Saigon photo department, came back from an assignment. Horst argued by telex with the New York head-office that an exception must be made, with the compromise that no close-up of the girl Kim Phuc alone would be transmitted.

The New York photo editor, Hal Buell, agreed that the news value of the photograph overrode any reservations about nudity.

The photo was then electrically transmitted, line by line, in 14 minutes, on a manually dialed radio-phone call with a Muirhead K220 transmitter with a supplementary AM/FM converter.  AP had this equipment stationed next to the switchboard at the Saigon PTT's (Post and Telegraph) telephone exchange in Saigon. The radio conditions were favorable that day and the picture, along with three other photographs of then incident reached the Tokyo photo bureau of The Associated Press.  From Tokyo the radio signal coming from Saigon was auto-relayed on AP controlled land and submarine wire communications circuits to New York and London, and from there to AP offices and newspapers around the world.

AP's bureau chief Richard Pyle recalled in an April 2000 interview that Horst Faas said "I think we have another Pulitzer here" when he looked at Ut's film through his magnifying glass in 1972.  Horst added in the same interview: "It remains one of the most perfect news photos I have seen in my fifty years in photo journalism."

To shoot his Pulitzer prize winning photograph Huynh Cong 'Nick Ut' used the Leica M-2 body with the serial number 1923019 with a 35mm Summicron lens, serial number 1923019.  It had not been AP's practice in 1972 to equip staff photographers with the German-made Leitz (Leica) cameras and lenses. Nikon equipment was the standard AP issue. However, every staff photographer of AP in Vietnam, eventually used his "own Leica" equipment, following the example of Horst Faas, who arrived  in Vietnam in June 1962 with his "own" Leica equipment coming from an assignment in Algeria.

Expense accounts and some fudging in the acquisition of "capital investments", i.e. cameras, lenses etc., in Hong Kong or from the black market in Saigon helped the photographers get their high-quality Leica cameras and lenses.

Nick Ut's elder brother, who died in battle in October 1965 used, of course, a Leica camera. Thus it was only natural that his little brother Ut eventually also had his own Leica. When Nick Ut was evacuated from Vietnam at the end of the war he took the camera and lens with him - and used both until the late eighties. He only lost his 50mm Leica lens in the hasty flight from Vietnam in 1975.

Other equipment used to shoot scenes around the "Kim Phuc incident" included a Nikon F body, with 200mm, 300mm and a wide-angle lens.

The Leica and 35mm Summicron are today exhibited at the Science Museum in London, along with Nick's pictures and a wire photo drum transmitter of the Muirhead K220 type that transmitted Ut's photographs from Saigon into the world on radio waves.

A check with the Leitz archives in Germany showed that Nick Ut's camera was produced in Germany in 1965.