Simply put, primary sources can be defined as: "original material, produced during the time being researched, by someone with first-hand knowledge of the event."1 Let's look more closely at that definition:
To be a primary source must be original to the time period and place being studied. For example, while a vintage sewing pattern would be a primary source, a new dress created with it would not be as it was made with modern materials and techniques not necessarily available at the time.
We often think of research materials as being primarily published text-based: journal articles, books, theses, and so on. Information comes in a huge variety of forms, and primary sources, while they do include textual materials like letters, government documents, and diaries, valuable information is also contained in photographs, maps, objects, sound recordings, films and videos, artworks, and photographs. Some examples are Jim Wong-Chu's photographs of Vancouver's Chinatown in the 1970's, Marie Curie's journal (still radioactive), archival CBC news footage of the mass spraying of the "miraculous" pesticide DDT, in the Maritimes, and the alarming early dental tools from Harvard's Dental School.
Sources of the time may be published or created during the time of the event, like a newspaper article, photograph, or flyer. They can also be captured later, in oral histories, biographies, or interviews, based on experiences and memories from the time. For example, while the Diary of Ann Frank is a primary source, depicting the experience of a young Jewish girl during the Holocaust and written during that time, the memoirs of Viktor Frankl are also an excellent primary source of the Jewish experience during that time, though it was written after the fact.
In order to be a primary source, it must be a first-hand experience. For example, a newspaper article about the 1990 Kanesatake Resistance in Quebec, written by a journalist like Dan David, who was present during the event, would be considered a primary source for that event, even though it was published years later. Interviews and Oral histories, like the ones created by the Canadian Museum of Immigration about new immigrants' first day in Canada are also good examples, as are autobiographies like the one published by Toronto restauranteur Jen Agg about growing up in Scarborough and experience in the business.
A document can sometimes be a secondary source for one research topic, but a primary source for another. For example, the 1996 Government of Canada report from the Royal Commission on Aboriginal Peoples provides primary evidence of the recommendation of the Commission, and the attitudes toward Indigenous, Aboriginal, First Nation, Inuit, and Metis relations in Canada, but would be a secondary source when it comes to details regarding residential schools.
1 Shmoop University Inc. [Shmoop]. (2015, February 19). What is a primary source? [video]. https://www.shmoop.com/video/what-is-a-primary-source. Shmoop homework help and study guides for students.