Mr Cobbe realised the significance of the painting after visiting an exhibition at the National Portrait Gallery where he saw a portrait that had until 70 years ago been accepted as a life portrait of Shakespeare.
The 31-year-old duchess was last seen in public on Friday, when she and Prince William visited the National Portrait Gallery in central London for the unveiling of her first official portrait.
The biggest rise was at the Scottish National Portrait Gallery, which was refurbished in 2011.
National Portrait Gallery director Sandy Nairne said Heldens had offered "a quiet but evocative study".
Man Ray Portraits is at the National Portrait Gallery in London until 27 May 2013.
The portrait of Golding is included in the exhibition at the National Portrait Gallery.
One contender was the new national portrait gallery being housed in the former American embassy, opposite Parliament.
An artist who has painted his sitter for nearly 20 years has won the National Portrait Gallery's art prize.
The portrait, called HRH The Duchess of Cambridge, is on display as part of the National Portrait Gallery's Contemporary Collections.
They will be honoured in an exhibition at London's National Portrait Gallery, to mark 40 years of the Press Gazette.
In 2009, a painting of Shriver with several Special Olympians was added to the permanent collection of the National Portrait Gallery.
Her work has been exhibited in many collections, including the Tate and the National Portrait Gallery, she has won wide recognition.
Two artists shortlisted for this year's BP Portrait Award at the National Portrait Gallery have been chosen for their impressions of their children.
Two years ago their partnership was captured on canvas when she and Neil agreed to pose for a portrait for the National Portrait Gallery.
Off-stage Bussell was made a CBE in 2006, her image was made in wax for Madame Tussauds, and her portrait hung in the National Portrait Gallery.
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Examples of his work are held at Government Art Collection, Arts Council of Great Britain, National Museum of Wales, National Portrait Gallery and Walker Art Gallery, Liverpool.
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Also in the arts world, Donmar Warehouse artist director Michael Grandage, National Portrait Gallery director Sandy Nairne, artist Gillian Ayres and textile designer Celia Birtwell were appointed CBEs.
But few works, since Francis Picabia's depiction of Marie Laurencin as an imaginary machine, challenge convention as much as the portrait of Sir John Sulston by Marc Quinn, recently unveiled at the National Portrait Gallery.
Next door is the National Portrait Gallery and just across the road is the attractive church of St Martin in the Fields, where you can enjoy free classical music recitals at 1pm on Mondays, Tuesdays and Fridays.
But more often at least in the 19th century, when women took to the deserts and forests in some numbers the travellers who feature in an exhibition which opened on July 7th at London's National Portrait Gallery dressed themselves like maiden aunts, in perfect imitation of the conventions they defied.
As a result of lottery lolly the National Portrait Gallery, the Museum of Scotland, the Millennium Stadium in Cardiff, the Dulwich Picture Gallery, the Wallace Collection and many others have had a makeover, bringing them up to modern standards in terms of access, educational facilities, exhibition space and more.
Some citizens criticise pieces displayed at the Smithsonian as conservative, but there is much to say in their defence: some exhibits, particularly in the National Portrait Gallery, are pretty cutting-edge, and the Smithsonian is trying to encourage love of the arts among Americans as a populace, not satisfy avant-garde envelope-pushing.
Portrait Salon was formed last year and describes itself as a form of Salon des Refuses - an exhibition of works rejected from a juried art show - that aims to showcase the best of the rejected images from the Taylor Wessing Portrait Prize, which is organised annually by the National Portrait Gallery (NPG).
The National Gallery of Scotland was closed by a security staff strike, while only the ground floors of the Scottish National Gallery of Modern Art, the Scottish Portrait Gallery and the Dean Gallery were open.
BBC: NEWS | UK | Scotland | Civil servants take strike action
An egregious example was a late Rembrandt portrait from Vienna, which ought not to have travelled, but which was shown at the National Gallery in London last year.
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