Eyeballing the data line they provide makes me think most people struggle to date photographs. What surprised me is the magnitude of the effect in photos that

Eyeballing the data line they provide makes me think most people struggle to date photographs. What surprised me is the magnitude of the effect in photos that were clearly taken after the advent of widespread mainstream colour photography. I'd have guessed the difference between the colour and non-colour groups would shrink considerably since colour would be much more a reflection of artistic choice than technological or resource constraint.