Harsh late-afternoon light is best avoided in photography. But here, it forms a brutal reality check--documenting typical conditions for men, women, children and animals on the Oregon and California Trails: "Uphill, Dusty and Monotonous."

Only those delayed by bad luck came through here in prime photographic light near sunset.

Photography dates from 1839 and many early emigrants would not have heard of it. Only later would the trails and a few users be photographed.