My friend Cynthia Moody, who has died aged 89, was a film-maker and editor by profession and devoted her retirement to documenting, safeguarding and promoting the work of the sculptor Ronald Moody, her uncle. Ronald's Johanaan, carved in elm in 1936, has frequently been on display since its acquisition by the Tate in 1992. His high standing as a sculptor owes much to Cynthia's astute judgment and persistent diplomacy.
Cynthia was born in London. Her mother, Ruby, was Welsh. Her father, Charles, was born in Jamaica and then became a dentist in Britain. Harold, her eldest uncle, was the founder of the League of Coloured Peoples.
Cynthia spent part of her childhood in Jamaica, returning to Britain aged 13. After secondary school, and a brief spell in the Women's Royal Naval Service, she worked for the Shell Film Unit, receiving a thorough training in all aspects of film. She became a respected director and editor, setting up two companies – one for documentaries, the other advertisements. Much travel on the continent was involved, and collaboration with leading directors and actors such as Alberto Cavalcanti, Peter Finch and Jacques Tati. Her documentaries included one about first world war veterans returning to France, which was broadcast on Channel 4 on Armistice Day.
Upon Ronald's death in 1984, and soon after she moved from London to Bristol, Cynthia inherited his estate. The practical and administrative skills of her career in film were put to brilliant use. She traced work already sold or missing: the return to Britain of Midonz (1937), after almost 60 years in US gallery storage, was a triumph of detective work and perseverance.
She entered all known details of each work, and a photo, on to "dope sheets" which are close to a definitive catalogue raisonné, now held at the Tate archive. All unsold work was sensitively displayed and tended in her spacious Bristol flat while she lived there. Cynthia's promotion of Ronald's work ranged from texts in scholarly journals to productive approaches to leading art collections. Solo shows of Ronald's work were mounted at Tate Britain and Tate Liverpool in 2004.
Cynthia was fiercely insistent that Ronald be accepted as a British artist and avoid the marginalisation which dogged him in his later years. She maintained good contacts with art institutions in Jamaica, setting up a Ronald Moody award. In Britain, she established fruitful friendships with artists of Caribbean birth or ancestry.
Wherever Cynthia worked, travelled and lived she made staunch friends. She was immensely sociable; her cooking and her parties were legendary and her all-consuming laughter infectious. Two Bristol friends enabled her to live independently at her flat with her beloved cats almost to the end, despite her failing memory.
Cynthia's first marriage, and later ones to Neil Arden and David Hussey, ended in divorce.