Mummy Brown paint made from ground-up remains of actual Egyptian mummies is believed to have been used in several works hanging on the walls at Cannon Hall country house museum near Barnsley.
VIDEO: Watch our exclusive video report above with Dr Stephen Buckley carrying out Mummy Brown tests on paintings at Cannon Hall.
Mummy Brown was one of the favourite colours used by English Pre-Raphaelite painters and tubes of the paint were still being sold until the early 20th century.
Now archaeological chemist Dr Stephen Buckley is carrying out forensic tests on paintings and believes he will find mummy remains in paintings in galleries all over the country, including Cannon Hall.
Amongst them at the Cawthorne venue is an 1884 canvas by Evelyn de Morgan called Love’s Passing and he believes Mummy Brown may have been used to paint a section of it top right, featuring the Grim Reaper - the personification of death.
Mummy Brown was a rich brown bituminous pigment, intermediate in tint between burnt umber and raw umber, originally made in the 16th and 17th centuries from white pitch, myrrh, and the ground up Egyptian mummies, both human and feline.
In the 16th century, there was a thriving trade in mummified remains between Egypt and Europe - mummy powder was said to have a mysterious life force that was transferrable to whoever used it, so it was applied to the skin or mixed into food and drinks.
Later, in the 18th century pigments from mummies came into fashion, with the “fleshiest parts” of the cadavers allegedly “providing the finest colours” and it was mass-produced in shops across Europe.
By the early 20th century, the pigment fell from popularity mainly due to the realisation that the paint was actually made of real Egyptian mummies, a significant decline in the number of mummies available and an increasing awareness of the scientific importance that mummies had.
Dr Buckley's research coincides with the opening of a new photo exhibition at the museum, called Resurrecting Ancient Egypt: a Monumental Yorkshire Journey, with photos by Huddersfield-based Kyte Photography showcasing the pyramids, obelisks, sphinxes and temples built around the county over the past 300 years.
It is curated by his partner and BBC TV Egyptologist Joann Fletcher, the third and final in her series of Ancient Egypt in Yorkshire exhibitions for Barnsley Museums which run until next year.
They were both part of a team of scientists who won a BAFTA for the 2011 Channel 4 documentary Mummifying Alan: Egypt’s Last Secret, which involved mummifying taxi driver Alan Billis, to replicate rediscovered secrets of the complex ancient process, at Sheffield’s Medico-Legal Centre.
Dr Buckley, a Research Fellow at the Universities of York and Tübingen in Germany, said of his Mummy Brown research: "Here at Cannon Hall what's really excellent from my point of view is that we believe we've got mummies in the paintings, as bizarre as it sounds.
"I'm looking at an example where Mummy Brown is likely to have been used to paint the Grim Reaper. So given the ancient Egyptian connection with death and mummies then that is quite a nice twist really."
He added: "It may seem strange to us now but Mummy Brown paint was literally made from ground up Egyptian mummies. This rich brown colour was used in paintings, particularly by the Pre-Raphaelites. Great artists at the time, in the late 19th century, often unknowingly were actually using Egyptian mummies to create beautiful works of art.
"As strange as it may be to us today, until the very early 20th century you could still buy Mummy Brown paint, with adverts in the Daily Mail.
"So it was used all around the country. There will be paintings like this in galleries all over the country."
"One of the great things about my work is that I take a forensic approach as to the analysis of these paintings, so I take tiny, tiny samples that you can barely see, to discover what is in there. Places like the National Gallery have scientists similar to myself who do exactly this and we are able to determine the composition of the paints using latest scientific technology, so it has no impact on the pantings themselves."
* Resurrecting Ancient Egypt: a Monumental Yorkshire Journey is at Cannon Hall until February 18; Gods’ Land in God’s County, featuring romb artefacts, is at Experience Barnsley at the Town Hall until January 20; From Sackville Street to the Valley of the Kings: the Art of Harold Jones, a collection of watercolours and drawings by the Barnsley-born artist-turned-archaeologist, is at the town centre's Cooper Gallery, until January 6.