The following year, 1948, the volcano sent many cubic metres of rock skyward sporadically. This showy display turned out to be just building momentum for a lava eruption in February 1949 which lasted three weeks and sent out a plume of ash six kilometres long. Colour photography was still rare at that time, but six years later in 1954 when Ngāuruhoe erupted again, amateur photographers had access to Kodachrome to record the drama. This time the volcano produced six million cubic tonnes of lava, expelled as energetic fountains of red magma spurting above the summit. Compelled by images of this wondrous natural spectacle, Len felt there was an analogy to the combination of fire and clay in his nascent practice as a potter. Although the volcanic series of bowls did not eventuate until 50 years later, his approach to the subject was galvanised by his youthful close encounters.

Len’s achievements with glazes in recreating the intense red of lava or the turquoise blue of a crater lake also owe a debt to his early enthusiasm for nature photography. He began photographing in colour himself in the 1960s, originally using 35mm slide film. He writes: “The volcanic and geothermal localities of the central North Island are areas to which I have returned many times…to record on film the detail and drama of these fascinating places…Here at your feet, and in the air you breathe, are the feverish exhalations of volcanic activity. These sites are the art galleries of nature’s creators. Thrust to the surface from subterranean crucibles, boiling water and gases create ephemeral or slowly evolving abstract patterns.”

It was not until 1992 when Len was chosen as one of 13 ceramicists by curator James Mack to exhibit at the World Expo that these visual effects found expression in clay. The theme for Expo that year was “The Voyage of Discovery”, to commemorate the 500th anniversary of Columbus’s expedition to the Americas. Located on the former site of a ceramics factory, New Zealand contribution was titled “Treasures of the Underworld”. Len’s instruction from James Mack was to create ceramics that would make manifest “the natural energy of the land and sea – suggesting magma bursting forth, then cooling as it flowed into the blue Pacific Ocean”.

Previously, Castle had evolved new shapes and glazes experimentally, but here he was forced to abandon the intuitive approach in order to express the imposed theme or idea. His response is a blend of two worlds. Rather than illustrate a particular place literally with these bowls, Len chose to sharpen the contrast between the rugged, scoria-like exteriors and the blood-like runs of red lava or cool, pooling blue on the interior, using his library of photographs to guide him. The interplay of colour and texture would sustain him well beyond Expo, and into a new century of practice.

Linda Tyler