Petworth House: Anti-ageing laser used for skin conditions helps restore historic chair

An anti-ageing laser usually used for treating skin conditions has been used to restore a historic chair at Petworth House.

The Erbium YAG laser is more typically used to treat skin conditions such as blemishes, scars, wrinkles and damage caused by the sun.

And National Trust conservators saw its ability to work on historic objects with painted and gilded surfaces.

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There had been a number of attempts in the past to redecorate the chairs, but various shades of paints had been used on different chairs and all had suffered dirt and wear.

Laser cleaning Petworth chairs - Picture: (C)National Trust - James Dobson

The conservators at the Trust’s Royal Oak Foundation Conservation Studio have been developing techniques for removing stubborn layers of non-original overpaint or dirt with the laser, to reveal the original finish of the object underneath.

It has been used on a chair from Petworth House, which is one of a set of nine, highly ornate chairs in an Italian style – known as sgabelli (stools) popular in Italy in the late 1500s.

The set at Petworth is likely to have been purchased in 1636 by Algernon Percy, 10th Earl of Northumberland (1602–68) originally for his house in London. The chairs were documented at Petworth in the 1750s.

Curator Rebecca Wallis explained the history of the chairs: “These fabulous chairs, influenced by the Italian style, are some of the earliest pieces of furniture here at Petworth and among the National Trust’s most beautiful treasures. It would have been possible to perch on these chairs, perhaps while waiting in a hall, they were not comfortable and were chiefly designed to impress and furnish a grand chamber or gallery.

Petworth - displaying the conserved chairs Picture: (C)National Trust - James Dobson

“Although we think Algernon Percy bought them for his London house, they were noted as being moved to his home at Petworth, in the Marble Hall, in 1750. Guests who may have used these chairs over the years include the artists Anthony van Dyck and J. M. W. Turner, who both visited and whose paintings are in the Petworth collections.”

The first task for the Trust’s conservators was to consolidate the original timber structure, and later historic repairs, so the chairs were stable.

The usual technique used by the conservators to remove overpaint on objects is with carefully chosen solvents applied to very small areas at a time, but one of the Petworth chairs had required a different approach.

Emma Schmuecker, the head of the conservation studio at Knole in Kent said: “One of the chairs had layers of aged bronze paint over the original gilding. Our usual approach wasn’t removing it effectively, so we turned to the laser which, combined with appropriate solvents, lifted it away cleanly.

“The laser is a very new tool for conservators and here in the studio we have been exploring its benefits for removing this type of paint from oil gilded surfaces. In the right circumstances it is proving a very useful addition.

“The aim has been to stabilise and improve the appearance of the chairs. Following cleaning, we have been able to achieve that as well as painting in small losses from wear. The set of chairs now have a consistent appearance as they would originally have had.”

Hilary McGrady the Trust’s director general said: ““We are deeply committed to looking after all of the collections in our care, not just using the best of tried and tested methods but also the latest technology. I am delighted we have been so successful in conserving an object of this beauty.”

Conservators identified the wood used to make the chairs as oak and elm, so they are now considered likely to have been made in England rather than Italy Their date has been confirmed by dendrochronology (tree ring analysis). The examination of similar chairs in the UK is now being undertaken by conservators and it is hoped this, together with analysis of cross-sections from the paint schemes, will enable a better understand their manufacture.

The chairs are among the first items to be conserved as part of a £3 million gift from the American Royal Oak Foundation to support the charity's collections conservation for the next five years.

Of the set of nine chairs, six have already been returned to Petworth where they are exhibited on specially commissioned plinths in the mansion’s North Gallery, giving visitors the opportunity to enjoy their fine detail and subtle variations in design.

The chairs, together with a rare Elizabethan globe and one of only three surviving complete statues showing the Roman Emperor Nero (AD 37–68) as a young child, are just a few of the extraordinary objects and their stories newly displayed at Petworth, as well as others at more than 50 Trust places this autumn. Each item is also explored in a new book, 125 Treasures from the Collections of the National Trust.