The phrase "a documentary through which" is correct and usable in written English.
It can be used when describing a documentary that serves as a medium for conveying information or telling a story.
Example: "The documentary through which we explored the impact of climate change was both informative and eye-opening."
Alternatives: "a documentary that conveys" or "a documentary via which".
She directed and produced the award-winning Breaking Through, a documentary in which openly LGBT elected officials share their stories of self-doubt and triumph over multiple barriers ranging from race and poverty to gender and sexual orientation, revealing a deeply personal, rarely-seen side of politicians and gay people.
The British-based artist was last in town in 2011 when "Exit Through the Gift Shop," a documentary in which he appeared (albeit with his face and voiced masked), was up for an Oscar.
Finally, we employed a documentary video, which provides a baseline for evaluation with narrative-based videos.
Sue Rubin wrote "Autism Is a World," a documentary film which in 2004 received an Oscar nomination for documentary short subject.
An exploratory research was conducted, including literature review and documentary analysis, through which we identified the main requirements of interaction between product and user.
A documentary about Stargate, which follows the duo from childhood through to their careers in America, aired in Norway on 25 February 2012.
A documentary, entitled Dirty Pictures, which explores Shulgin's lifetime quest to unlock the human mind through psychedelics, is touring film festivals worldwide at the moment.
Lopez featured in the 2007 PBS documentary Brown Is the New Green: George Lopez and the American Dream, which used his career as a lens through which to examine the commercialization of Latino culture.
This is a disturbing documentary which, through the testimonies of three courageous whistleblowers, sheds some daylight on the USA's secret military drone programme.
He is the eldest of four brothers, all of whom are goalkeepers, and apparently each goalkeeper gets better the later they were born (the youngest is only eight and was recently featured in a Canal Plus documentary, in which he was seen flying through the air to tip a shot over the bar).
