It is a building site, a cat's cradle of scaffolding that took three months to put up and which, unless you knew better, it would be hard to picture as a room housing one of the most jaw-dropping collections of old masters anywhere in the world.  The Wallace Collection, in central London, reopens its great gallery to the public on 19 September 2014, two years after a £5m project to transform a space that is normally home to spectacular works including Frans Hals' The Laughing Cavalier and Nicolas Poussin's A Dance to the Music of Time.  The gallery's director, Christoph Vogtherr, said the revamp was on budget and on time. "It is a unique moment. For most of us working here, it is the biggest thing we'll see happening here."  One of the main aims is to allow natural light back into the room by replacing a ceiling from the 1970s that was packed with air-conditioning ducts. A new lighting scheme will also be installed, and the coral pink cotton damask on the walls will be replaced with crimson silk damask.  Besides the Hals and the Poussin, the gallery is home to one of Velázquez's most famous paintings, The Lady With a Fan, and Rubens' The Rainbow Landscape.  Vogtherr said: "The head curator of the Getty once told me that when they are discussing acquisitions they sometimes ask: is this good enough to be in the great gallery? If it is, they consider buying it."  What makes it extra special is that the gallery cannot, under a stipulation made in 1897 when the collection was bequeathed to the nation, lend any of its works. It is the only place people can see them. "It is a panorama of what happened in Europe in the baroque age, from Spain to the Netherlands, from England to Italy," said Vogtherr of the collection. "There are a lot of really wonderful conversations going on that wouldn't happen anywhere else."  Money for the work was provided by the Monument Trust, a charitable body set up by the Sainsbury family. The plan is to begin rehanging in the spring.  The great gallery was built by Sir Richard Wallace between 1872 and 1875 as part of an extension of Hertford House, required to accommodate a collection built up largely by the fourth marquess of Hertford. Then, it was possible to see his family's amazing artworks one day a week, on application; today, the Wallace Collection is a national museum showing not just art but furniture, art and armoury.  It used to be a secret pleasure, adored by people lucky enough to know about it. It's not so secret any more, with the gallery about to announce record annual visitor numbers of more than 400,000 – in spite of the great gallery's closure in October 2012.  "We're starting to discuss what we will do if the success continues because we might hit a point in the not-too-distant future when, on the weekend particularly, the building is just not large enough," said Vogtherr.  Having said that, He stressed, however, that the Wallace did not want to change its "very special" nature. It is a place that people can, and do, drop into, maybe to have a look at just three paintings.  It is also a place without plinths or ropes or glass over the art. Vogtherr said: "If we get to a point where we seem to be processing numbers rather than welcoming our visitors, it will turn against us and against what we are. We have to keep that personal and immersive quality."
It has always been a space where visitors can drop in on old masters as if they were old friends. So will the Great Gallery's personal touch be able to survive its £5m transformation?