After five years, chemists find way to save cloaks

Rangi Te Kanawa inspects an old cloak belonging to Audrey Harris (on her left) at the NorthTec marae in Raumanga. Photo / APN

Deterioration of Maori taonga held at Te Papa will be a thing of the past with the development of a process to stabilise acids that eat away at the fibres of korowai, or cloaks.

Textile conservator Rangi Te Kanawa, who comes from a family of Ngati Maniapoto weavers, has been working with Victoria University associate professor of chemistry Gerald Smith to stop the decay.

The biggest problem institutions have in keeping articles such as piupiu (skirts) intact is the breakdown of traditionally dyed black flax fibre. It is made by soaking muka from the plant in tannin, which is found in hinau, kanuka or manuka bark. It is then immersed in grey mud known as paru. Paru is acidic and degrades the fibre, leading to it breaking down into powder.

Muka also has high hemicellulose content, which produces acetic acid, presenting more challenges for conservation efforts - 10 per cent of the national museum's collection of 350 to 400 cloaks are extremely fragile.

"The black is shedding and things break down. It's very brittle and dry. That brittleness fragments, breaks with movement, and it causes a collapse in the weave," Ms Te Kanawa said.

It has taken five years to develop a zinc-alginate consolidation treatment that is showing promising signs of mopping up the acids and, importantly, binding fibres together so that patterns are not lost. But it was an option of last resort, Ms Te Kanawa, said because it was irreversible.

"All the treatments we do we try to make reversible because such is science that in the future some bright spark might come up with a better method. In theory they've all got to be reversible but this one is not."

Her late mother, Diggeress Te Kanawa, and grandmother Dame Rangimarie Hetet were master weavers. Diggeress had definite ideas about conservation, Ms Te Kanawa said.

"In museums this is what the practice is, you preserve collections. But Mum's approach is a very Maori approach - nothing is ever supposed to last forever.

"As a weaver she'd always say, 'Oh well, you make another one'. That's all right for Mum, bless her soul.

"I'm encouraging weavers to look at our taonga and to try to replicate them but that is a huge call because I don't know whether the weavers today have as much time as the weavers had in our traditional time. Some of these taonga, it would take a weaver almost a lifetime to make a complete replica. They're huge and the work is extremely fine."

However, it was better to do something now to save the clothing. The new development could see the lifetime of a piece extended for 10 years, meaning more exhibitions and chances for the public to see them.