Lumen is the name for a unit of light – a gradient of radiance. It is also an anatomical term for a bodily cavity or conduit, such as an artery, along which blood flows. These two meanings converge in the metaphor of ‘light at the end of a tunnel’; an expression that helps light a way into Sutapa Biswas’s film Lumen, setting the scene for its fluctuations of clarity and darkness, its alternating states of euphoria and trauma, its lurches between poetry and pathology. The film begins with the story of a baby emerging from a womb, and ends on a note of departure, with its female protagonist about to embark on a journey across uncharted waters. In between, we are entrusted with a series of intimate scenes from a life, recounted in an episodic monologue whose dramatic ebb and flow is sharply illumined by flashes of memory but indelibly haunted by fears and doubts.

The journey in question is inspired by the one undertaken, six decades ago, by the Biswas family. A passage from India, an exit precipitated by the artist’s father’s political beliefs, this abrupt uprooting continued to disturb and unsettle her mother. A lament for the sights and sounds of India she and her family had to leave behind on their protracted sea voyage to England, the film is also an angry reproach of centuries of colonial rule, and its implacable incursions on domestic life. Where history has often marginalised the female voice, Biswas reinstates it, not just as mainstay of family and home but as avatar of social conscience. Mixing archive material and newly filmed footage to embellish its bravura central monologue, Biswas lends this deeply personal narrative a compelling universal resonance. Seen through a glass darkly, Lumen sheds unflinching light on the ripple effects of a complex and turbulent past.