Start with a broad category
The Library of Congress’ guide to documentary and actuality films describes nonfiction forms including newsreels, biographies, travelogues, scientific films and investigations. It also discusses how filmmakers’ perspectives and funding can affect selection and presentation. The word documentary therefore identifies a broad field, not one guarantee about how every shot, interview or sound in a particular work was produced.
Ask what the film is doing with its material
A film may explain, investigate, remember, argue or observe. Look at the stated subject, creator and production context before deciding which expectation to bring. If your question concerns an historical event, separate the filmed evidence from the narration or later interpretation built around it. A confident voice and a factual category do not make every conclusion self-proving.
Keep descriptions fair to the actual method
Calling something reconstructed, observational or archive-based requires evidence about that work. Do not label a scene a reconstruction simply because it is well lit, or describe a film as unedited reality because the camera moves freely. Read the creator’s notes and catalogue information where available. If those do not settle the method, preserve the uncertainty instead of converting a viewing impression into a production fact.
Choose a film for the question you want to explore
A biography may suit an introduction to a person, while an investigation or a contemporary archive item can serve another purpose. Compare the actual work descriptions rather than expecting all documentary searches to return interchangeable answers. Keep the release date visible, too: an older nonfiction film can be valuable for its period without being a current update on the subject it depicts.
Questions, answered
Does documentary mean every scene was filmed spontaneously?
No. The category includes a range of forms and production approaches.
Should a documentary’s date and commissioner matter to a viewing choice?
Yes. They help establish its context, purpose and relationship to the question you are exploring.