An old photo of Hangzhou. [Photo provided to China Daily by Shen Hong]

In 2006, Shen contacted Sewall to study the lives of his parents and grandparents in China for his research. Then, Shen learned about the photo collection and encouraged Sewall to scan them and finally co-published the photo book with him.

"While I scanned his photos, which took several months, I got to known Robert (Fitch) better," writes Sewall. "I saw his intense interest in temples, boats, bridges and people."

The other book, Kaleidoscopic Views of the West Lake, also published by Shen, is a collection of photos taken by the late Sidney Gamble, who was a good friend of Fitch. The two men bonded over a common interest - photographing China. But unlike Fitch, Gamble didn't live in Hangzhou.

His first visit to the city in 1908 was with his father, David Gamble, a founder of Procter & Gamble, the US consumer-goods company.

After studying at Princeton University and the University of California in Berkeley, Sidney Gamble visited China several times between 1917 and 1932 to conduct surveys that later resulted in his studies of Chinese society and culture. He used some photos in his academic publications and lectures, but the majority of the images was never exhibited in public.