To reveal the paintings, the scientists used a technique called multi-illumination hyperspectral extraction (MHX), which involves taking dozens of images in the visible, infrared and ultraviolet bands of light and processing them using statistical algorithms developed at the National Research Council of Italy in Pisa, said team member Vincenzo Palleschi, a senior researcher at the research council. The technique can detect Egyptian blue, a color developed in ancient Egypt that "has a very specific response in a single spectral band," Palleschi said. The team also analyzed the residual remains of other remaining colors to help determine what colors were in...