From the Oxford English Dictionary and the Society of American Archivists Dictionary of Archives Terminology:

primary source n. material that contains firsthand accounts of events and that was created contemporaneous to those events or later recalled by an eyewitness

Primary sources emphasize the lack of intermediaries between the thing or events being studied and reports of those things or events based on the belief that firsthand accounts are more accurate. Examples of primary sources include letters and diaries; government, church, and business records; oral histories; photographs, motion pictures, and videos; maps and land records; and blueprints. Newspaper articles contemporaneous with the events described are traditionally considered primary sources, although the reporter may have compiled the story from witnesses, rather than being an eyewitness. Artifacts and specimens may also be primary evidence if they are the object of study.

Archives are the gatekeepers of primary source material

Archives provide first-hand information or evidence relating to historical events or figures

Archive: A place in which public records or other important historic documents are kept

Archive: A historical record or document so preserved

Digitize: To convert (analogue data, esp. in later use images, video, and text) to digital form, typically for storage or processing by a computer; to represent in digital form

Guidelines for primary source literacy from the Society of American Archivists

Protocols for Native American archival materials from the Society of American Archivists

Statement on the Fair Use of Images for Teaching, Research and Study from the Society of American Archivists