In 2014, French auctioneer Marc Labarbe received a phone call from a friend. The attic of their Toulouse home had yielded a surprising discovery: a painting, coated in dust and stained by a water leak, that looked all the same to be something of value. Labarbe approached gingerly, cleaning one of the painted faces with cotton wool and water. He sent a photo to the art appraiser Eric Turquin, based in Paris, and then he waited.
Five years later, Turquin sat in front of the painting in Colnaghi, a London gallery, as staff fretted over the lighting: The spotlights were reflecting off the varnish on the artwork, which stood five feet tall and six feet wide, obscuring its detail from certain angles.