To restore a painting, science must meet art and the past must meet the present

Paintings wear their years as people do. Colours fade, surfaces craze with cracks and spot with age. Although it is natural to think of them as permanent, in truth they are constantly evolving, nursed along the way by teams of highly trained and dedicated conservators. ‘The longer I’ve worked in my profession, the more I have come to see that we are walking beside these great paintings through time,’ says Rebecca Hellen, head conservator of easel painting for the National Trust. ‘They are changing just as we are.’

How to deal with those marks of passing time is a question with which every picture restorer wrestles. ‘There are contrasting traditions in conservation in southern and northern Europe,’ explains Alisa Vincentelli, a freelance conservator who has worked at Tate Modern, The Bowes Museum and Auckland Castle, as well as for Christie’s. ‘My first experience as a picture restorer came as a volunteer in the conservation room at the Byzantine and Christian Museum in Athens. In northern Europe, we tend to try to make “invisible” repairs, whereas in Italy and Greece, damage is often integrated into the painting — it becomes a part of its story.’

Pinpointing exactly which moment in its life to which a picture should be taken back is a key part of the restorer’s role. ‘Leaving aside the repair of damage, for most private clients the judgement is aesthetic,’ says Marine Andrieux, who trained as conservator at the Sorbonne and, after spells at the V&A Museum and Tate, is now a painting restorer with the long-established family firm of Everett Fine Art in Somerset. ‘Paintings that have been in families for generations are often simply so dirty [people] can’t see them anymore. At the moment, I’m working on a Cedric Morris still life that’s been hanging in the owner’s sitting room more or less since it was completed. Morris used very thick impasto, which forms a surface that dust and dirt really cling to, so it requires very extensive and careful cleaning’.

Hidden behind a door and undisturbed for centuries, this magnificent painting proved to be The Judgement of Paris by Francesco Trevisani. Its discoloured, dark varnish was cleaned by Everett Fine Art.

Dust and dirt deposits are removed using a soft, wide goat-hair brush, together with specially adapted vacuum-cleaner nozzles, with specialist solvents that can remove yellowed varnish without damaging the paintwork beneath. In the past, treatment was not always so gentle. Before the 1950s, the everyday job of caring for pictures was generally entrusted to household cleaners and restoration was carried out by local artists.

‘They came in and removed layers of oxidised varnish, often using caustic substances such as lye, vinegar and even urine. It not only took off the varnish, but often some of the surface paint, too. Then, they’d retouch it with oil paints as they saw fit,’ Hellen explains. Today, Andrieux notes, restorers are trained to be more cautious and minimal. ‘We want to repair the damage, not add to it.’ The appalling vision of the notorious 2018 ‘Monkey Christ’ restoration of Ecce Homo in the Sanctuary of Mercy church in Borja, Spain, haunts the nightmares of conservators the world over.

‘We base restoration on historic facts and scientific analysis,’ Hellen explains. Her work on Thomas Moran’s Nearing Camp, Evening on the Upper Colorado River, 1882, for example, involved ‘X-rays, a chemical analysis of the paint and a cross section of the canvas that revealed red pigment bubbling up through the greens and browns like a miniature volcano.’ Alongside that came a two-week field trip to Washington DC to consult with American conservators who had worked on Moran’s epic landscapes. ‘The decisions you make as a conservator in caring for a painting are based on the time you meet the artwork in its life and the time that you are in your own life,’ Hellen says. ‘As much as we try to understand the painting, the judgements we make will always be subjective.’

For that reason, Vincentelli believes, when it comes to the modern art restorer: ‘The most important thing is that we never do any work on a painting that is not reversible — because, however much we try to avoid it, there will always be some input from the era we are working in, whether that’s in terms of the materials or the aesthetics.’

Picture conservation is a profession that straddles the past and the present and even (almost) the future, requiring as it does both a detailed knowledge of materials that have been in use for centuries and an understanding of the latest scientific developments, such as the use of nanomaterials and lasers. It is work that combines the theoretical with the practical, art with analysis. Today, a large conservation department may use infrared reflectography to see through the top layers of the paint and pick out changes made by the artist. For example, in the spring of 2026, National Trust conservators discovered a ‘horse-drawn carriage, a lady in a bonnet, a gentleman and carriage dog’ hidden beneath the surface of a painting, Stourhead in its Infancy, by this very method.

X-ray fluorescence examinations, meanwhile, map the chemical compositions of pigment and can reveal hidden under-drawings. Pest infestations — common in old paintings — can be killed off in nitrogen chambers without damaging the canvas.

However, not every conservator works in laboratory conditions. Living in rural Northumberland with three small children to raise, Vincentelli created a studio in her home and worked on private commissions. ‘I’m pretty sure we were the only family in the village with a Salvator Rosa painting sitting on an easel in the spare bedroom,’ she says.

The joys and challenges of the conservator’s job come from both expected and unexpected quarters. The National Trust collection of about 13,500 paintings contains many that have had ‘interesting’ lives. ‘Often they were commissioned to display in London townhouses, before being transferred, as their owners’ fortunes increased, to country houses,’ Hellen reveals. ‘There, they would be moved around, reframed to fit in with the décor or changing fashion; often, they were made smaller, too, to fit into a new space.’

Perhaps the most dramatic example of the latter is to be found at Petworth House in West Sussex, long a centre of artistic patronage. ‘The celebrated Petworth Beauties, seven full-length portraits of Society ladies by Michael Dahl from the late 17th century were almost literally cut down to size by the 3rd Earl of Egremont in the 1820s,’ Hellen explains. ‘The Earl had the portraits removed from their frames and their legs were folded up behind their backs before reframing. The Beauties were in this uncomfortable position for nearly two centuries. We were given the task of bringing their legs back down again.’

Andrieux took pleasure in restoring a Turner painting of Caernarvon Castle in Wales (‘A tiny canvas that, amazingly, had one of his palettes stuck on the back of it’), but also found herself drawn in by the task of reviving an old metal sign from a West Country inn. ‘It was a vivid-green coat of arms and had swung back and forth outside the pub in the wind and rain for more than a century. Working on that, and other pieces that form part of people’s lives, is fascinating. The clients are so attached to these pieces that the reaction when we return them in their revived state is often quite emotional.’

This poignant portrait, which bears the monogram of the artist Henry Graves and was painted in 1871, had been stowed under a spare bed when its canvas weakened and fell of its stretcher. Restored by Everett Fine Art, it once more hangs in the house for which it was commissioned.

One of Hellen’s career highlights also involved Turner. ‘Mercury Sent to Admonish Aeneas was one of four paintings completed in 1850,’ she explains. ‘It was never sold and came to the National Gallery as part of the Turner Bequest. After that, it suffered some rather rough treatment. It [was] sent around the world on at least half a dozen occasions and for some years hung in the British Embassy in Athens. Turner used red and blue spermaceti wax in his paintings. It melts at 39˚C, so having it on the wall of an un-air-conditioned building in Greece in summer is clearly not what a conservator would recommend.’

This was not the only way the painting suffered: ‘At some point, it had been re-lined and the restorers had attached the failing canvas to a new canvas by pressing down on the surface with heavy, hot irons.’ Working next to Turner scholar Ian Warrell, Hellen set about tackling the picture’s restoration. ‘It gave me more sleepless nights than anything I have worked on,’ she recalls, ‘but also the greatest pleasure. The rollercoaster of trying to understand Turner’s process, rarely repeated from one canvas to the next, to unravel what he was doing with that incredible non-linear surface… it was totally beguiling.’

Not all conservation work ends so happily, alas. Vincentelli recalls restoring an abstract painted wooden relief by a leading British artist of the 1950s for a large institution (which shall remain anonymous). ‘Shortly after I returned the work, which was in muted shades of grey and brown, a firm of decorators came in to paint the room it was mounted in. They evidently thought it was some kind of fixture that was in need of brightening up and slapped emulsion paint all over it. They did quite a thorough job, apparently, but I’ve never had the heart to go and look at it.’

This feature originally appeared in the September 9, 2026, issue of Country Life. Click here for more information on how to subscribe