Manufacturing autochrome plates was a complicated process. According to England’s National Media Museum, it required coating the plates in potato starch grains dyed red, green, and blue-violet, then a layer of carbon black (charcoal powder), which filled in gaps between the grains, and then, finally, a panchromatic photographic emulsion. “If you look at one of the images, you can see the tunic was green. The question is, was it actually that hue of green? Was it darker or lighter? I’d be surprised if it was actually spot on because of the nature of the process itself, which wasn’t perfect,” said Matthew Butson, vice president of Getty Images’ Hulton Archive.