The moment has finally arrived! The doors of the Painted Hall are closed for the final time this year, as we prepare for Phase II of the Painted Hall project. Over the next six months a huge scaffold will be constructed in the lower hall, allowing our team of conservators to get up close to the 40,000 square of painted surface which will be absorbing their energies over the next three years.

This is not, however, the first time the Painted Hall has been conserved. In fact, the three-hundred-year life of the Painted Hall is one of continual conservation.

In 1727, with paint barely dry in the Upper Hall, the first campaign of conservation work was already underway. The ceiling was found to be deteriorating - atmospheric pollution and lack of ventilation the principle causes. The polluted atmosphere of London would become an increasing danger to the longevity of the paintings over the next 300 years.

Thus the first cleaning and ‘refreshing’ of the paintings occurred between 1733 and 1735. Further cleanings and repairs were executed at regular intervals of twenty years. Just as today, these projects were incredibly expensive, the 1777 work costing £1000, a huge sum at the time.

Most of these interventions involved varnishing – often coating a thin layer of wax over the painted surface in order to provide some protection against the elements. On successive occasions the previous varnishing was not removed, and by the twentieth century over fifteen layers of varnish had been applied to the paintings.

If badly applied, varnish can harm rather that protect a painted surface. Varnish can yellow with continued exposure to air, spoiling the clarity and colour of a painting. Varnish can also darken and, at a microscopic level, fracture, causing light to scatter and producing a white veil over the surface obscuring details – an effect known as ‘blanching’.  Another change to Thornhill’s work has been the restoration or repainting of some areas which had been lost owing to water damage or problems affecting the plastered surface.   

By 1938, the Painted Hall was in a sorry state of repair. The space had functioned as an art gallery for over a hundred years and the walls of the Lower Hall had been whitewashed and the windows blocked up. Major work was also required on the ceiling which no conservator had visited for some considerable time. Major conservation work in 1938 was recorded as leaving the hall ‘as sound as when completed’, but this was clearly not the case as just 20 years later another large-scale conservation project was necessary.

The 1957 – 1960 conservation campaign was carried out by a team from the Ministry of Works. An initial examination had revealed the painted surface to be  ‘covered with soot and grime and … heavily coated with varnish. So much so that the vestibule largely appeared to be painted in dark brown and the blue of the ceiling looked amber.’ To add to this, areas of the painting in the vestibule had been destroyed by water damage and bomb damage, and parts of the supporting timber structure above had been attacked by beetles.

A huge scaffold similar to the one designed for the upcoming project cut off all the natural to from the ceiling, allowing the conservators to work in safety. In places up to fifteen layers of varnish were removed, some of these layers strongly resistant to even the most potent solvents.

The work also included significant repainting or ‘restoration’. In places where no trace of the original drapery had lasted, the restorer constructed a model of cloth and plaster, as used by the painters of the 18th century, to serve as a basis for his reconstruction. The drapery was restored in the missing parts over a thin intermediate layer of varnish, and the procedure and colours of the original were followed, but in a medium less likely to darken and change with the time.

In the vestibule where the rafters above had been damaged by insects, the plaster was sawn into squares and removed. Once the rotten timber had been replaced (by a steel matrix) the plaster sections were re-fixed and then retouched to disguise the saw cuts.

In 1960 the scaffoldings were dismantled, and an exhibition held to display the Hall after its extensive restoration - opened by HM Queen Elizabeth II and visited by over 48,000 people. Considering that the paintings had been in such critical conditions at its outset, the project had been a resounding success, and numerous inspections over the coming decades revealed the conservation to be holding. By 1977, however, inspection reported that surface deposits were covering the paintings and that the varnish had become yellow and the retouchings had darkened as well as damage to the plaster. A report at the time concluded that ‘…the Painted Hall now needs to be cleaned again and resurfaced, although it is not urgent, it should be placed on the programme’.

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