 The Magdalen Reading was transferred from its original oak to a mahogany panel ( West Indian swietenia ) by unknown craftsmen sometime between 1828 and when the National Gallery acquired it in 1860 . Campbell states that the transfer was " Certainly after 1828 , probably after 1845 , and certainly before 1860 " , the year it was acquired by the National Gallery . Artificial ultramarine @-@ coloured paint found in the transfer ground indicates that the change of panel took place after 1830 . The heads in Lisbon are still on their original oak panels . The Stockholm drawing was discovered in a German inventory c . 1916 and is likely of Swedish origin . It was bequeathed by a Norwegian collector , Christian Langaad , to the Swedish National Museum of Fine Arts in 1918 . 
 The Magdalen Reading was transferred from its original oak to a mahogany panel ( West Indian swietenia ) by unknown craftsmen sometime between 1828 and when the National Gallery acquired it in 1860 . Campbell <a href='uninflect' title='1'><mark>states</mark></a> that the transfer was " Certainly after 1828 , probably after 1845 , and certainly before 1860 " , the year it was acquired by the National Gallery . Artificial ultramarine @-@ coloured paint found in the transfer ground <a href='uninflect' title='2'><mark>indicates</mark></a> that the change of panel took place after 1830 . The heads in Lisbon <a href='drop_aux' title='3'><mark>are</mark></a>still on their original oak panels . The Stockholm drawing was discovered in a German inventory c . 1916 and <a href='drop_aux' title='4'><mark>is</mark></a>likely of Swedish origin . It was bequeathed by a Norwegian collector , Christian Langaad , to the Swedish National Museum of Fine Arts in 1918 . 
The Magdalen Reading was transferred from its original oak to a mahogany panel ( West Indian swietenia ) by unknown craftsmen sometime between 1828 and when the National Gallery acquired it in 1860 . Campbell state dat the transfer was " Certainly after 1828 , probably after 1845 , and certainly b4 1860 " , the year it was acquired by the National Gallery . Artificial ultramarine @-@ coloured paint found in da transfer ground indicate tdatthe change of panel took place after 1830 . The heads in Lisbon still on their original oak panels . TdaStockholm drawing was discovered in a German inventory c . 1916 and likely of Swedish origin . It was bequeathed by a Norwegian collector , Christian Langaad , to thdawedish National Museum of Fine Arts in 1918 .