"It was the most exciting discovery that the National Gallery found," paintings conservator Angela Zehnder told News24.
Rachel Alexander discovered a hidden face in the Charles Hazelwood Shannon work, The Morning Toilet (1912) with an X-ray examination.
"X-radiography penetrates all the layers of the painting. It is the result of the materials used and their thickness. Lead white blocks the X-rays and these appear white. X-rays, when this pigment is used, shows a positive correlation, where the image you get from the X-ray relates tonally to the X-ray."
Zehnder said that SA could not compare with the advances in international technology conservation such as the work done by the ESRF at the Van Gogh Museum Amsterdam. However, she alluded to collaboration between South African and European art experts.
"The Van Gogh Museum is a leading institution and we look to learn from them. They create a micro-climate for each of their artworks because they have to travel to other institutions. It's an exercise that requires considerable funding."
South Africa does not have many art conservators, and these have had to learn their craft from people who qualified in the UK or US.
"There are few art conservators in South Africa and we need to start looking at a situation where people can train here. There's a need to develop through the universities or at museum level. There is no proper training in South Africa," National Gallery director Raison Naidoo told News24.
The technology to restore art has evolved to become less "high-tech" in SA to give the works the best chance of being preserved with non-invasive procedures.
In the Van Gogh paintings, the scientists employed an X-ray beam of microscopic dimensions to reveal a complex chemical reaction taking place in the incredibly thin layer where the paint meets the varnish. Sunlight that hits the painting triggers a chemical reaction that turns the yellow pigment brown.
"I've visited conservation studios in New York and hot tables are rarely used. We are the jewels of Africa because of our conservation programme and with technology, less is more," Zehnder said.
In Africa, art conservation is still in the "developmental stage" according to Zehnder, but SA was instrumental in assisting Mali to conserve the Timbuktu manuscripts as a cultural heritage.
"We built a museum and had a number of exhibitions, but there are lots of issues: Some manuscripts are still sold to tourists so it becomes an issue of poverty," said Naidoo, who was part of the project.
He said that throughout Africa, art treasures were removed during colonial times and that he would support efforts to return them to the countries of origin.
"In the past you would have people say: 'You guys don't have proper facilities to store them [art works].' But if you look at the Mali project for example, you will see that those excuses fall away. So I would support the return of those works. The heritage of a country belongs there."
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