The science of sightseeing

Prussian Blue Researchers

Prussian Blue Researchers at Diamond
(Credit: Courtesy of Diamond Light Source)

Are you a beach holiday kind of person, or more into city breaks? Whichever kind of break you prefer, it’s likely that you’ll spend some of your time sightseeing. And wherever you are in the world, chances are that science has been helping to keep your chosen site in tip-top condition.

In 1999 the first international conference on synchrotron radiation in art and archaeology was held at Daresbury Laboratory, where SRS scientists were at the forefront of the exploitation of synchrotron radiation in support of heritage science. The SRS was used to study historic objects and processes, covering a wide range of ancient materials including parchment, paper, textiles, masonry, ceramics, glass, glazes, metals, timber, bone, paintings and pigments. Synchrotron radiation proved to be a powerful new tool for archaeologists, conservators and art historians. Primary areas addressed were the identification of states of degradation, corrosion pathways and insights into historic production technologies.

These investigations help in the preservation of our cultural heritage and in our understanding and appreciation of the societies that created them, and can even help develop solutions to modern problems. The work continues at our state-of-the-art science facilities.

In the art gallery

Specialists from the Tate Gallery are looking after 30,000 artworks by 19th century painter JMW Turner. Bequeathed to the gallery on his death, his watercolours are painted with pigments that fade with exposure to light and air. The aim of the research was to discover which gases would be best to include in air-free display cases, to conserve the paintings whilst giving the public the best possible view of the work. Working with samples of Prussian Blue, one of Turner’s favourite pigments, scientists at Diamond Light Source used a strong, artificial light to replicate 20 years of fading in just 10 minutes. X-rays were used to show the resulting changes in the microstructure of the pigment, the ultimate goal being to convert the data gathered to useable conservation knowledge.

Sculpture

A sculpture tested using Micro-SORS
(Credit: ICVBC, Ital)

Researchers from the Technical University of Catalonia in Barcelona used an infrared microbeam at Diamond to investigate the decay of the silver foil used to illustrate images of saints on medieval churches and altarpieces. Many of the images have been badly damaged by the corrosive effects of air on the organic-based glues and varnishes that hold the foils in place, or cover them. Their findings, that the decay is directly related to contact with the atmosphere, will inform future conservation efforts.

It’s not just synchrotrons that can help with heritage science - using lasers to identify the chemical makeup of materials reduces the risk of damage to precious paintings during conservation and restoration work. Scientists from the CLF have joined forces with researchers from the Institute for the Conservation and Promotion of Cultural Heritage (ICVBC), part of Italy’s National Research Council (CNR), to develop a technique that uses Raman spectroscopy to provide a chemical fingerprint for the identification of pigments in artworks and manuscripts, and the composition of archaeological finds.

Researchers tested this technique on an artificial surface of painted layers, prepared to mimic a real painting. They were able to assess the chemical make-up of each individual layer. The next step is to optimise the sensitivity and depth penetration, and apply the technique to real artwork. The ultimate goal is to develop a portable scanner.

And the CLF has supported investigations, in collaboration with University of Durham, on the pigments used in Northumbrian manuscripts dating from as early as the mid-seventh century. The Durham Gospels is thought to be one of the precious books made on the Holy Island of Lindisfarne around 650 AD. The Raman analysis characterises the wide range of pigments used in the decorated illuminations found on its pages.

Heritage Science at Queen's University Belfast
(Credit: Queen's University Belfast)

At the museum

Mary Rose

Cutaway illustration of the Mary Rose
(Credit: Mary Rose Trust)

The raising of the Mary Rose, Henry VIII’s flagship, from the bottom of the Solent gripped a generation of children, as they followed the salvage operation on television with Blue Peter. Scientists have been conserving the timbers for 30 years, using pioneering techniques, and the remains of the ship are now being carefully dried in a dedicated museum in Portsmouth. But whilst they were on the sea floor, sulfur compounds reduced by bacteria made their way into the wood. Until 2013, the ship was being continually sprayed with polyethylene glycol, which is used to replace the water in the wood, to limit shrinkage and collapse upon drying. Now that the drying process is underway, great care has to be taken as the reduced sulfur can react with oxygen to form sulfuric acid that destroys the cellular structure of the wood. This has the potential to seriously compromise conservation efforts and is particularly a problem near nails, bolts and shrapnel, where the presence of iron ions acts as a catalyst for the oxidation process.

Monitoring the sulfur concentrations in timber samples, and how they change over time, is a long term project. Work began at the SRS, and is continuing using X-ray absorption spectroscopy at Diamond. Initially the team needed to understand the processes involved. Now that the drying process is underway, the wood needs to be monitored to ensure that it doesn’t degrade (via oxidation, or the activity of bacteria) into harmful compounds over time. Access to a synchrotron is crucial for this work, which couldn’t be carried out in a university laboratory.

Deformed tibia

Laser scans a deformed tibia to test for chemical abnormalities
(Credit: UCL)

Wood samples aren’t the only artefacts from the Mary Rose to have been examined at the Rutherford Appleton Laboratory. Around thirty gold coins were recovered with the wreck, and as we know the date on which the ship sank, the coins can be accurately dated. Researchers brought the coins to the GEM instrument at ISIS to be examined using neutron diffraction. We now know that the coins were made by striking, and the research has given us a more precise understanding of the Tudor minting process.

The CLF has also been working with the Mary Rose Trust, using Raman spectroscopy to analyse the bones of its sailors. Researchers from the Royal National Orthopaedic Hospital (RNOH) and University College London (UCL) also joined the team, which tested two sets of shin bones from the ship. One set appeared anatomically healthy, whilst the other bones were abnormal in shape.

The results of the Raman study confirmed that the abnormal bones have chemical abnormalities associated with rickets. Rickets is a metabolic bone disease that was common in Tudor times due to the poor diet of the average person, and this work is helping to develop non-invasive techniques to diagnose this and other bone diseases in living people.

Supporting businesses at I-TAC: Heritage Science Services case study
(Credit: STFC)

Out in the field

Roman jug

Roman jug from Kent excavations
(Credit: Oxford Archaeology)

Archaeologists working on the Highways Agency scheme to widen the A2 between Pepperhill and Cobham in Kent unearthed some bronze artefacts from two high-status Roman pit burials, some of the best ever seen in Britain. The artefacts, nearly 2000 years old, included jugs and vessels for mixing wine, as well as ceremonial objects. They were brought to ISIS for a non-destructive, detailed analysis of their crystal structure. At this point in history we know that Britons were beginning to take on the cultural practices of the Romans, and one of the aims of the investigations was to compare these artefacts with similar ones from Pompeii, to see if they had been imported from elsewhere in the Roman Empire, or made here.

And new advances in palaeontology mean that the fossilised remains of dinosaurs are now supporting advances in nuclear technology and biomedical research. Mountains of new information has emerged from the study of ancient fossils, as Diamond’s bright beams give long-dead creatures a new lease of life. Millions of years after they became interred in the ground, the elemental make up of fossils can still provide vital clues as to how ancient creatures lived and died.

Phil Manning

Phil Manning is one of the UK's leading dinosaur experts
(Credit: Diamond Light Source)

Phil Manning, a dinosaur expert from the University of Manchester, is keen to highlight the interdisciplinary nature of his palaeontology, and the benefits that brings. During their synchrotron studies of dinosaur bone, his team discovered that the bones had locked away certain elements from their surrounding environment - the calcium phosphate in the bones had taken up radioactive elements from the environment in which they were buried. Now we know that calcium phosphate has these properties, it may be that we can use it to engineer new structures that can safely store nuclear waste over long periods of time – an ancient solution to a very modern problem.

And there may be medical benefits to studying dinosaur bones as well. Bone injuries cause specific chemicals to be released by the body, which leave behind traces in the bones. Dinosaur experts can tell whether a creature fully recovered from an injury or died with unhealed wounds, all based on the chemical traces locked within the fossil. Our body chemistry is similar enough to the dinosaurs’ that understanding how their bones broke and healed, and the trace elements involved in this process, could help inform future developments in the treatment of injury and bone disease.

So whether you’re spending a rainy day at the museum, soaking up some local culture at the art museum, or enjoying the great outdoors with a tramp around ancient ruins – spare a thought for the scientists helping to conserve the world’s treasures, and those using ancient inspiration to solve pressing modern problems.

How to Build a Dinosaur: A Gorgosaurus Comes to Diamond Light Source
(Credit: Diamond Light Source)

Science and Technology Facilities Council Switchboard: 01793 442000