By Don Ford

SAN FRANCISCO (KPIX 5) – Standing nearly four stories tall and almost ninety years old, one of the Grace Cathedral’s largest stained glass windows is in serious trouble.

“We need to take the panels out now, before we have catastrophic failure,” said Ariana Makau, owner of Nzilani Glass Conservation.

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This priceless work of art depicting the New Testament has been beating back the weather since 1931. The old lead channels are falling apart, holes are letting water in. Repairs were made decades ago, but done poorly.

This one window alone has three hundred and three panels, holding more than 5,000 pieces of glass. Before anything is touched, every single piece is carefully studied, measured and recorded.

It takes a special team said Greg Sondern, the cathedral’s canon sacrist. “We’re bringing Ariana in because her credentials are so stunning. She really closer to a museum curator than she is to a glass fixer person,” Sondern said.

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With a crew of five, every panel will be repaired and restored at a special facility in Oakland. Sometimes there are hidden messages left inside the lead lining, dates or a personal greeting from artists, hundreds of years ago.

“But sometimes, and this is the Holy Grail, your actually get the signature of the artist who painted that piece,” Makau said.

Grace Cathedral won’t say how much this massive restoration conservation project will cost, that’s being covered by a private donor who wishes to remain anonymous.

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The church said it’ll be months before the job here will be done, but said they’ll have it completed in time for Easter 2016.