Mystery solved: The origin of the colors in the first color photographs

A palette of colours on a silver plate: that is what the world's first colour photograph looks like. It was taken by French physicist Edmond Becquerel in 1848. His process was empirical, never explained, and quickly abandoned. A team including CNRS researchers has now shone a light on this: the colours obtained by Edmond Becquerel were due to the presence of metallic silver nanoparticles.