Please note: subtitles in French are available.
Conservator Nicole Ryder explains the process of conserving the Gallery's portrait of King Edward VI and the Pope.
The portrait goes on display as part of The Real Tudors: Kings and Queens Rediscovered at the National Portrait Gallery, London, from 12 September 2014 to 1 March 2015.
Find out more about the conservation project, supported by Bank of America Merrill Lynch: ow.ly/xSer8