British Museum blog

Scientific investigation of the Norwich shroud

Janet Ambers, Scientist, British Museum

Research Fellow Emma Passmore taking UV images of the shroud. © Norwich Castle Museum and Art Gallery / Trustees of the British Museum

Research Fellow Emma Passmore taking UV images of the shroud. © Norwich Castle Museum and Art Gallery / Trustees of the British Museum

    This is the latest in a series of posts about the unfolding of the Norwich shroud, a joint project between the British Museum and Norwich Castle Museum and Art Gallery

With the shroud unfolded for the first time (although still in need of much conservation attention) David Saunders, Keeper of Conservation and Scientific Research, Emma Passmore, Mellon Research Fellow, Caroline Cartwright, scientist, and I made our first visit to see what had been revealed on the inner surface.

David has a longstanding interest in the use of imaging techniques to enhance and investigate painted surfaces, and our main objective was to examine areas where text has been applied.

Using specialist cameras, we took both infrared and ultraviolet images of the shroud. Infrared reflectography is often employed in research into paintings to reveal initial sketches under the final images. For the shroud, it will make the black text clearer. This will help John Taylor with his interpretation of the hieroglyphs while the conservators continue to treat the shroud, and also allow the hieroglyphs to be published clearly for international scholars.

Imaging with ultraviolet light may help to show surface coatings and stains. Both of these approaches are very useful for objects like this as they provide information without the need for sampling, or indeed for any contact with the surface at all.

Caroline Cartwright, who specialises in fibre identification (amongst other things), took tiny samples of the linen ground (approximately two to three millimetres long) both with and without pigment.

Examining them under the scanning electron microscope (SEM) allowed her to positively identify the fibres as linen, and give the conservators information about their construction and condition.

SEM image of a fragment of the Norwich shroud. © Norwich Castle Museum and Art Gallery / Trustees of the British Museum

SEM image of a fragment of the Norwich shroud. © Norwich Castle Museum and Art Gallery / Trustees of the British Museum

The images here clearly show the weave of the textile, the twist direction of the fibres, and pigment sitting on the surface of the linen fibres (which appears white under the SEM). It also shows how few breaks there are in each fibre, confirming their good condition, and how surprisingly clean they are, suggesting the shroud may have been kept mostly in a folded state, and/or not extensively disturbed, be it by repeated opening and folding, handling, study or display.

SEM image of linen fibres from the Norwich shroud. The lack of tears in the individual fibres confirms what good condition they are in. © Norwich Castle Museum and Art Gallery / Trustees of the British Museum

SEM image of linen fibres from the Norwich shroud. The lack of tears in the individual fibres confirms what good condition they are in. © Norwich Castle Museum and Art Gallery / Trustees of the British Museum

My main role is to identify the pigments used. To enable me to do this Melina Plottu, our textile conservation intern from France, collected samples of the various pigments. She removed tiny pieces of single fibres with traces of colour on and placed them between two slides. I took these back to our laboratories and examined them under the microscope of a Raman spectrometer.

Textile conservation intern Melina Plottu carefully places a sample of linen with traces of colour on it into a glass vial held by scientist Janet Ambers.  © Norwich Castle Museum and Art Gallery / Trustees of the British Museum

Textile conservation intern Melina Plottu carefully places a sample of linen with traces of colour on it into a glass vial held by scientist Janet Ambers. © Norwich Castle Museum and Art Gallery / Trustees of the British Museum

This equipment uses changes in the wavelength of a laser beam shone on to a material to provide an absolute identification.

Raman showed that both the light and the dark black pigments are based on carbon. There is a possibility that crushed charcoal was used for this, but the most common Egyptian black ink is known to have been produced using soot (sometimes called carbon black in the art world).

Why some areas of black text on the shroud are much lighter than others is not yet clear. The colour in the red ink comes from hematite, an iron oxide. This is responsible for the colour of red ochre, a form of red coloured earth extensively found throughout Egypt and frequently used as a pigment in Egyptian art.

Taking a sample from the shroud. © Norwich Castle Museum and Art Gallery / Trustees of the British Museum

Taking a sample from the shroud. © Norwich Castle Museum and Art Gallery / Trustees of the British Museum

Melina and Monique Pullan, the textile conservator leading the conservation, have also found a single area of white pigment, used around the area of a cartouche in the centre of the shroud. This proved to be gypsum, a white mineral common in Egypt.

Wall painting from the eighteenth dynasty tomb chapel of Nebamun. The skin of the central seated figure and male slave are coloured with red ochre © Trustees of the British Museum

Wall painting from the eighteenth dynasty tomb chapel of Nebamun. The skin of the central seated figure and male slave are coloured with red ochre © Trustees of the British Museum

The conservators were reassured to know it wasn’t huntite, another white mineral sometimes used as a pigment in Egypt – its sensitivity to moisture would have precluded many of the water based treatments used to relax and realign fragile fibres.

Filed under: Conservation, Norwich shroud

One Response - Comments are closed.

  1. Dan says:

    I love the electron microscope pictures!

    Like

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Another brilliant photo of the Museum’s Main entrance on Great Russell Street – this time by @violenceor. The perspective gives a good sense of the huge scale of the columns. The Museum has two rows of columns at the main entrance, with each being around 14 metres tall and 1.5 metres wide. Designer Sir Robert Smirke used 44 columns along the front elevation. This design of putting columns in front of an entrance is called a ‘portico’, and was used extensively in ancient Greek and Roman buildings. #regram #repost #architecture #neoclassical #BritishMuseum The Museum looks spectacular with a blue sky overhead – especially in this great shot by @whatrajwants. You can see the beautiful gold flashes shining in the sun. This triangular area above the columns is called a ‘pediment’, and was a common feature in ancient Greek architecture. The copying of classical designs was fashionable during the late 18th and early 19th centuries, and was known as the Greek Revival. The sculptures in the pediment were designed in 1847 by Sir Richard Westmacott and installed in 1851. The pediment originally had a bright blue background, with the statues painted white. #regram #repost #architecture #neoclassical #sculpture #gold #BritishMuseum Concluding our short series of gold objects from the Museum’s collection is this group of items found in the Fishpool hoard. The hoard was buried in Nottinghamshire sometime during the War of the Roses (1455–1485), and contains some outstanding pieces of jewellery. 1,237 objects were found in this hoard in total. At the time it was deposited, its value would have been around £400, which is around £300,000 in today’s money! The variety of this collection of objects includes brilliant examples of fine craftsmanship. The turquoise ring in the centre was highly valued as it was believed that turquoise would protect the wearer from poisoning, drowning or falling off a horse.
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See this incredible Art Car as part of our #SouthAfricanArt exhibition, which opens 27 October 2016. You can book your tickets now by following the link in our bio.

Esther Mahlangu (b. 1935), detail of BMW Art Car 12, 1991. © Esther Mahlangu. Photo © BMW Group Archives.
#SouthAfrica #history #art #design
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