'The Wilton Diptych': Ultramarine
Why was natural ultramarine pigment so expensive and how is it used in 'The Wilton Diptych'?
Richard II presented to the Virgin and Child by his Patron Saint John the Baptist and Saints Edward and Edmund ('The Wilton Diptych') (about 1395-9) by English or French (?)The National Gallery, London
'The Wilton Diptych' dates from the late 14th century and was made by an unknown artist working in England or France. It is one of only a small handful of English panel paintings to have survived from the Middle Ages.
This portable diptych is a painting made on two hinged wooden panels. It was created for Richard II, who was King of England from 1377 to 1399, and was likely intended for his own use, for private prayer.
The inner panels show a young King Richard II surrounded by three saints - Edmund, Edward the Confessor, and John the Baptist. These saints present the king to the Christ Child and his mother, the Virgin Mary, who are surrounded by a gathering of angels.
Richard II presented to the Virgin and Child by his Patron Saint John the Baptist and Saints Edward and Edmund ('The Wilton Diptych') (about 1395-9) by English or French (?)The National Gallery, London
The backs of the panels are also decorated - here we see Richard's coat of arms displayed on the left and his emblem of the white hart on the right.
Richard II presented to the Virgin and Child by his Patron Saint John the Baptist and Saints Edward and Edmund ('The Wilton Diptych') (about 1395-9) by English or French (?)The National Gallery, London
One of the first things you notice when looking at this painting is the intense and beautiful blue colour used in the right-hand panel. The blue pigment used here is a precious material that has sometimes been even more expensive than gold.
Map of the route from the lapis lazuli mines in Badakhshan (in present day Afghanistan) to Europe (2024)The National Gallery, London
Natural Ultramarine
This blue pigment is natural ultramarine.
The name ultramarine translates as ‘beyond the sea’ – this refers to the fact that it is made from a mineral that had to be imported to Europe from Badakhshan in present-day Afghanistan, one of the very few places it occurs naturally.
Pile of natural ultramarine pigment (1999)The National Gallery, London
Natural ultramarine was expensive, not only because of the difficulty of obtaining the mineral, but also because it needed careful processing to purify it to produce the best blue colour.
Sample of lapis lazuli mineral (1999)The National Gallery, London
How is it made?
Natural ultramarine pigment is made from the mineral lapis lazuli, a semi-precious stone that is also used for jewellery. The stone contains the blue mineral lazurite, mixed with other minerals such as calcite and iron pyrite (fool's gold) which appears as tiny golden flecks.
Richard II presented to the Virgin and Child by his Patron Saint John the Baptist and Saints Edward and Edmund ('The Wilton Diptych') (about 1395-9) by English or French (?)The National Gallery, London
This combination of minerals means that the lapis lazuli can’t simply be crushed to a powder to make a good blue pigment – this would result in a greyish-blue material without the intense colour we see in 'The Wilton Diptych'.
The crushed mineral must be further processed – traditionally this was done by mixing it with resin and wax to make a mass with a dough-like consistency. This mass would be kneaded in an alkaline solution made from wood ash, during which the blue pigment leaches out.
Natural ultramarine pigment samples from the different stages of collecting the pigment (2024)The National Gallery, London
The process of kneading and collecting pigment would be repeated many times, with the first steps giving the best quality blue pigment (pictured on the right), and later steps producing increasingly paler and greyer material (shown on the left).
Photomicrograph of NG4451 (detail of an angel’s curls over a blue robe)The National Gallery, London
Under the microscope
Examination of 'The Wilton Diptych' under the microscope reveals that a really high quality natural ultramarine pigment, with large intensely blue particles, has been used. This can be seen in this detail from one of the angel's curls over a blue robe.
Paint cross-section sample from the shield on the outer panel of NG4451, photographed under the microscopeThe National Gallery, London
These large deep-blue particles can also be seen in a paint sample taken from the blue and gold shield on the outer panel. In this sample the blue paint layer is covered with an off-white adhesive layer and a gold leaf layer which form one of the fleur-de-lis decorations.
Richard II presented to the Virgin and Child by his Patron Saint John the Baptist and Saints Edward and Edmund ('The Wilton Diptych') (about 1395-9) by English or French (?)The National Gallery, London
The expensive nature of this pigment meant that it was associated with high status. It was often used to emphasise important features in paintings, such as the clothes worn by the Virgin Mary.
Ultramarine continued to be a rare and precious colour until the 19th-century.
Find out how and why ultramarine became more widely used by artists from the 19th century to the present day...
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