Primary sources are defined as items of many formats that have not been created based on other materials or interpretations and reflect an original representation of a time or event. Such items consist of letters, newspaper reports, photographs, recordings of first-hand observers, paintings or sketches, and realia that may reflect a specific time, people, culture, or other phenomena.
Primary sources are often contemporaneous to a specific period or event but can also be created later, sometimes many years later, for example, the retelling of an eye witness through an oral history or personal accounting. This is a key concept so let's look at some examples of 'primary' versus 'secondary' sources:
Primary sources include items such as autobiographies, data, first person accounts, government documents, oral histories, original research findings, photographs, research methods, and results, or speeches.
Secondary sources include such things as abstracts of articles, biographies, chronologies, dictionaries, encyclopedias, paraphrased quotes, and textbooks.
Contemporaneous works fall into a special category, and almost always apply only to social science and humanities. Contemporaneous works can be considered primary sources if they were produced or originated at the same time as the subject matter in question. So, artworks, books, documentaries, journal articles and newspaper reports, for example, which are generally secondary sources can be primary if they are contemporaneous to the subject or the research.