KETAKI SHETH clearly remembers her first encounter with the Sidi, India’s small and closed community descended from Africans, when she approached one of their villages in a Gujarat forest in 2005. "It was like entering a dusty film set. There was a gated entrance, a chai stall and four boys wearing t-shirts and baseball caps playing carrom (a board game). They did not look at me in a welcoming way…that gave me my first lesson [in how] this community lived so exclusively."

Yet Ms Sheth, an Indian photographer from Mumbai who had spotted the village of Jambur by chance, was undeterred. She went on to spend five years visiting Sidi settlements, becoming entwined with the families and taking pictures along the way. “A Certain Grace: The Sidi—Indians of African Descent”, the resulting book of 88 black-and-white photographs, was launched in Mumbai last month.

Relatively little is known about the Sidi, whose ancestors are African slaves, soldiers, traders and some Muslim pilgrims who wound up in India throughout the centuries. Historians believe the first wave arrived in the 9th century when Arab-led armies that used African slaves as soldiers took over the Sindh province, which is now in southern Pakistan. Central Asian armies carrying out invasions in the following centuries brought more. Some Sidi were accomplished soldiers who rose through the army ranks. A few even became the royal families of small principalities set aside for their community. A second, and generally less-skilled, influx followed in the 17th century when the Portuguese brought slaves from their trading posts in Africa to Goa, their colony in India.

The Sidi today remains a tiny group of 35,000-70,000 people in a country of 1.2 billion, mostly concentrated in the rural areas of Gujarat and Karnataka in the west and south-west of the country, although some live in cities such as Mumbai and Hyderabad. After centuries in the subcontinent, the Sidi’s languages, cuisine and clothes are completely Indian. Most do not even know from which African country they originally hail. Yet they are undeniably linked to their roots through music and dance. The Sidi’s Goma music—with its polyrhythms, call-and-response singing and winding dance moves—is thought to be drawn from the Ngoma style of the east-African Bantus. (Ngoma is a Swahili word that means both drum and dance.)

Most Sidi are Sufi Muslim, and some are Christian or Hindu. One photo shows a man putting out incense in his village’s Sufi shrine; another shows a young girl wearing a beautiful batik hijab. The Sidi broadly oppose marrying outside the community and in some cases expel those who do. They are among the country’s poorest groups; one of the “scheduled tribes” which qualify for extra government welfare schemes.

Ms Sheth found the Sidi just as fun-loving as they were private: "Every Friday they gather at the dargah (a Sufi shrine) and they dance and sing…it's a community that loves happenings and loves dressing up." One of her favourite shots in the book shows a young woman getting ready for a wedding reception amid a blur of helping hands. Another striking image shows a grinning dancer shattering a coconut on his head while performing for one of the community’s royal families.

Ms Sheth’s previous work includes a book of portraits of twins from families in India and Britain with the surname Patel. She has also published a book of documentary-style Mumbai street photography—her long-time mentor was Raghubir Singh, one of India's most famous photographers and a master of urban shots. Known for her old-school approach, she always uses a manual camera and shoots in black-and-white. She attributes this partly to falling in love with the darkroom process while studying photography at New York University in the 1980s: "NYU had these glorious darkrooms with revolving doors and chemicals that came out of pipes...when I got back to Bombay I set up a darkroom in my parents' house." Yet Ms Sheth admits that it might be time to move on from this traditional form and embrace digital technology and colour for her next project: “I have a technical block and I have to overcome it. I have to do this if I'm to carry on.”

A Certain Grace: The Sidi—Indians of African Descent. By Ketaki Sheth. Photoink; 107 pages;1500 rupees