The National Portrait Gallery of London (NPG) is set to unveil the true story behind the only surviving group portrait of the Brontë sisters with the aid of scientific testing, the Telegraph reported at the end of last week.

Painted by the Brontë’s brother Patrick Branwell in 1834, it originally featured the three sisters Charlotte, Emily and Anne separated by a pillar. As time passed and the paintwork faded a male face emerged from beneath the pillar, which was believed to be Branwell himself. Now experts from the NPG are using the latest scientific techniques to identify the shadowy figure once and for all.

Their findings suggest that Branwell originally intended to paint himself into the portrait but the idea was short-lived. By dating the paintwork in different parts of the portrait, the researchers have shown that the pillar was painted at the early stages of the work’s creation. Branwell only made preliminary sketches of a self-portrait before painting over them with the solid pillar and erasing himself for nearly a century.

It is yet another example of the artistic discoveries made possible through the use of science and technology. In September this year, it was reported that a hidden figure had been uncovered in Rembrandt’s ‘An Old Man in Military Costume’ using advanced x-ray analysis. A few months later, a study involving infrared reflectography and ultrahigh-resolution digital macro photography prompted researchers to declare that a masterpiece previously attributed to Hieronymus Bosch was probably painted by his studio.

For a long time, the existence of the Brontë group portrait itself was shrouded in mystery. Thought to be lost, it was known from an 1853 description by the author Elizabeth Gaskell. It was later discovered in 1914 folded up on top of a cupboard by the second wife of Charlotte Brontë’s husband, the Reverend A.B. Nicholls.

The painting and the research findings are to form part of ‘Celebrating Charlotte Brontë: 1816-1855’ a new exhibition opening at the NPG on 22 February 2016. It will mark 200 years since the novelist’s birth.