Jian Liu has kept 60 rolls of film hidden from public view for three decades.

He was a 20-year-old fashion design student in Beijing in the spring of 1989 when a student-led pro-democracy movement drew thousands of supporters to Tiananmen Square. Captivated by the spirit of the movement, he photographed the protests for about 50 days.

Mr. Liu said he had been exhilarated by the protesters’ bold demands for greater freedom and an end to corruption, and had set out to capture their enthusiasm and zeal.

“It made me think that this country would get better and better,” he said.

Then, on June 4, 1989, the People’s Liberation Army rolled into Beijing and opened fire at the activists and civilians, killing hundreds, possibly thousands.