Ice diving

As Co-Director of photography on the highly acclaimed 70mm IMAX production “Antarctica”, Malcolm Ludgate acs wanted to show not only the frozen continent in all it’s magnificence but also wanted to put the audience in places they would never be likely to go, under the frozen sea ice.

While filming sequences of Weddell seals and their pups, the team knew it was very important to follow them into the water where they would be totally at ease. These beautiful mammals move and look quite uncomfortable on the ice, but swim like ballet dancers under water, living quite happily in the sub zero conditions. Seals tend to gather around tide cracks and pressure ridges in the ice, where gaps in the frozen sea, created by the constantly moving ocean, give them an ideal entry point for diving. Here, the two-metre thick under ice surface, changes from an endless flat sheet, into a mass of huge jumbled blocks. The constant ocean movement, forces ice into miniature upside down mountain ranges and creates a perfect environment for the Weddell seals.

When ice diving in Antarctica, the logistics involved are enormous and everything has to run like clockwork. A shelter has to be erected to offer some form of protection from the icy wind, diving gear needs to be assembled and double checked and for filming, the large IMAX camera had to be loaded and prepared in its underwater housing. To work safely underwater and below ice requires special diving gear with back up systems for almost every piece of equipment used. If a diver was a hundred metres away from an entry point and something went wrong, it could be impossible to just come directly to the surface, as it would be frozen solid. Malcolm and his dive team used twin air cylinders, freeze resistant independent regulators, dry suits, safety lines and specialized accessories, to combat the sub zero conditions for the forty minutes or so each filming dive required. After suiting up and getting in the icy water, the team would search out and very carefully approach the seals, to avoid disturbing them.

Malcolm knew from experience, that film stock becomes very brittle at low temperatures and as they were working in air temperatures around minus 20° C and seawater at minus 1.9°C, the crew had to be extra careful. Even so, on several occasions while filming under the ice, the divers heard a sharp snap, as the film broke and the camera ground to a halt. It was disheartening to hear, because despite being chilled, it meant aborting the dive, getting everything out of the water, Mal stripping halfway out of his dry suit (so as not to drip salt water into the cameras mechanism), having to clean and reload the camera, reassemble the underwater housing and get back into the icy water.

Capturing the footage of the Weddell seals under the Antarctic ice was a difficult task, but well worth the effort. When the audience watches the footage on the huge Imax screen, they see the opaque ceiling of ice above, super clear water, the jet-black of the deep ocean below, and the graceful movement of the Weddell seals, it really does give the experience of diving below the ice.