A new film opening tomorrow in cinemas nation-wide examines the background to the iconic 1932 photograph of eleven work-men seated on a girder in New York. Paddy Kehoe talks to Éamonn Ó Cualáin, producer of Lón sa Spéir (Men at Lunch)

An iconic photograph taken in September 1932, 69 floors - or 850 feet - above 41st Street in Manhattan, has fascinated viewers in the decades since the shot first appeared in The New York Times, above the caption Lunch Atop A Skyscraper.

The image emblazons souvenir mugs and tee-shirts and can be seen framed in a myriad pubs around the world and in this country too.

Perhaps due to a dramatic angle the photographer may have chosen, the men appear to be sitting on a beam that is, for the most part, situated above a completely empty void at the Rockefeller Center construction site.

“If you fell, and if you hit your head off a girder on the way down you were going to get a serious injury or die, " says Eamonn Ó Cualáin, the producer of Lón sa Spéir (Men at Lunch).

"But it was natural for them to be in that situation - if they are up on the 69th floor they have been at that job, probably for the last six months. They’re comfortable with their surroundings, so that’s probably why they look so casual.” Actress Fionnuala Flanagan narrated the movie in Irish and English language versions. The Irish-language narration is subtitled in English.

Eamonn's brother Seán directed the film. Aside from the various photographs displayed in this deeply engaging documentary, the Ó Cualáin brothers had access to archive footage of the building of the Rockefeller Center. “We got that footage from the Rockefeller archive, that we transferred to HD ourselves, “ says Eamonn.

Watch out for the foreman who is waving his hands as he speaks, possibly issuing instructions. “It’s kind of surreal alright, the man waving and being so casual that height up in the air.”

Late Late Show viewers will have seen an elderly Boston man called Paddy O’Shaughnessy on a recent show, who had flown over from Boston to talk about the photograph. His interest is deeply personal, as he believes that the man at the extreme left of the eleven-strong group is his late father Mattie. Moreover, the man on the extreme right, holding the bottle and looking into the camera lens is believed to be his uncle Sonny Glynn.

Sonny’s son Pat Glynn also features in the film. This Irish family connection is the most endearing aspect of the film, even if there are no documents yet found to prove definitively who these two of steel-workers are.

Another photograph taken during construction of the Rockefeller Center shows two men called Eckner and Curtis, sleeping- or pretending to sleep - on the girder in question. “We couldn’t follow those threads because we only found their names on our last day filming. We did try to find out who they were afterwards, but nothing came out of it.”

The producer is almost certain that there will be a sequel in which the Ó Cualáin brothers investigate further the stories behind the rest of the men on the girder. Aside from Eckner and Curtis, there are three others who have been identified.

The iconic girder photograph of the men on the girder was hitherto attributed to the famous photographer Charles Evett. “But the credit has now changed to unknown because of the information we provided in the documentary, " says Eamonn. "There were three men taking photographs - one of them was called Kelly - but there was no evidence to put Evetts there on the day - which is not saying he didn’t take it.”

The ‘docu-drama’ element is limited to brief shots of actors at the beginning and end, seated and dressed like the eleven men in the photo. The very fact that they are moving their bodies a little and talking to each other, as the men would have been doing on that very day in September 1932 lends useful, dramatic impact.

Moreover, such CGI technology enhances and does not overwhelm this 68-minute celebration of that deeply resonant photograph. The Ó Cualáin brothers have made a perfectly-pitched, thought-provoking film, without resorting to the rather tired device of dramatic reconstruction that ruins so many documenatry films, when there is a paucity of archival footage. “We try to capture the feelings you get when you look at the photo in the film, so I hope we’ve done that,” concludes Eamonn.

Men at Lunch (Lón sa Spéir) is funded by TG4, the Irish Film Board, and the Broadcasting Authority of Ireland. The film opens tomorrow at Irish Film Institute, Dublin, Movies @ Swords, Dublin, Movies @ Dundrum, Dublin, Omniplex, Screen Cinema, Dublin, Omniplex Wexford, Omniplex Galway, MovieWorld, Gorey, Co. Wexford, MovieWorld, Castlebar, Co. Mayo. February 1 to 7.