Edinburgh-born Thomson first set off for Singapore in 1862 to join his brother there. He soon traveled to Malaysia, Sri Lanka, and eventually to Siam, which is now Thailand.

In 1866, he set off for Laos and Cambodia, before settling in Hong Kong in 1868, where he set up his photography studio.

At the end of 1870, the Scottish photographer set off for a major expedition on the Chinese mainland.

The subjects Thomson documented varied and included monasteries, imperial palaces, landscapes, architecture, and street scenes, as well as people going about their daily lives.

During his travels, he had to carry around a bulky, largely wooden camera, as well as many crates, glass negatives, and bottles of highly flammable chemicals used to develop the images.

“It’s so easy to take a photograph now, it’s taken for granted,” Yao said. “This exhibition shows tenacity and difficulty, and Thomson’s hard work has endured 150 years later.”

The exhibition runs until June 23.