Notre Dame is seen at the submerged bank of Seine River after continuous rainfalls in Paris
Geologists are studying about ten quarries north of Paris to find the same limestone as that mined for the cathedral underneath the French capital. That vast network of quarry tunnels beneath Paris was closed in the 18th century as collapsing galleries created dangerous sinkholes in streets and fields around the city.
Workers need new stone to rebuild collapsed parts of the vault and replace blocks in the gables over the three main entrances and other sections high up the side walls that were weakened by the fire.
Experts have been carefully testing the strength of surviving stones with everything from radar beams to simple mason’s hammers. Some stones that fell from the vault can be reused, but others have lost their inner solidity.
At the end of January 2021, fifty-two wooden support vaults left the Le Bras workshop for Paris, for the purpose of reinforcing each of the five stone vaults of the cathedral that were weakened or damaged, or sometimes gutted by the collapse of the spire during the fire of April 15th, 2019.
Assembly at the cathedral will begin in February 2021, thirty meters above the void: the supports will have been previously mounted under the vaults using hydraulic jacks.
On New Year’s Eve, electronic veteran Jean-Michel Jarre returned for a highly unique digital concert. Titled “Welcome To The Other Side,” the performance was filmed in a French studio but broadcast live in virtual reality (VR) inside a digital rendering of the Notre Dame de Paris Cathedral. Viewers could either tune in using VR or watch the set as a video on any device.
Of the medium, Jarre said,
“Virtual reality is to the performing arts today what cinema was to the theatre in its early days, a kind of curiosity. I believe that VR will become tomorrow, a mode of expression in its own right.”
The need to build scaffolds up to 40 metres high for the 200 workers to repair the high walls and soaring vaults has given art restorers the opportunity to study up close the side chapel ceilings they had no access to before.
They are finding traces of rich polychromatic decorations under the dark levels that have built up over centuries of candle smoke and air pollution. Medieval cathedrals were often covered inside and out with paint that either wore off or was hidden as unfashionable in later eras.
“We’ve found blues, reds, ochres … lilies with some gilding and others whose traces are preserved in negative”, chief heritage curator Jonathan Truillet told the daily La Croix.
People walk on the forecourt of Notre Dame’s Cathedral, on May 31st, 2020.
French officials are considering cleaning the inside surfaces of the cathedral with one of the newest technologies in art restoration: lasers. Chicago-based art restoration expert Bartosz Dajnowski invented the technique, which his company, GC Laser Systems, tested inside Notre Dame last month.
The technique uses light to weed out contamination without chemicals or mechanical abrasion, he says. Dajnowski’s lasers have cleaned the facade of the U.S. Supreme Court building and the lions in front of the New York Public Library.