A poetry film/documentary hybrid. The filmmaker, Kate Sweeney, describes it in the Vimeo description as

A poetic glimpse into the archives of the North East [UK] poetry publisher Bloodaxe Books, the contents of which were recently purchased by Newcastle University.
The film was made by artist Kate Sweeney in collaboration with poets Tara Bergin and Anna Woodford in spring 2013

Anna Woodford and Tara Bergin both held residencies at the archive. Bergin talks about her fondness for archives in a video introduction to the film. The same site (CAMPUS social network) gives a fuller explanation of how Proof came to be:

In 2013, Newcastle University acquired the archive of Bloodaxe Books, one of the most important
contemporary poetry publishers in the world. Two poets and recent PhD graduates, Anna Woodford and Tara Bergin, were asked to take a look into the as yet un-catalogued boxes to gain an initial sense of the archive’s scope and potential. To document their findings, they teamed up with artist Kate Sweeney to make a short ‘poem-film.’ They called it ‘Proof’.

“It was very strange and very interesting,” Bergin says.

The film includes guest appearances by Bloodaxe authors Gillian Allnutt, Simon Armitage, John Hegley and Anne Stevenson.