Dates

Normalized Dates

The normalized date fields (Type, Begin, End, and Certainty) are the primary way of recording dates. Except as described below, only these fields should be filled in (the Label, Era, and Calendar are set by default and should not be changed).

Date Expression Field

The Date Expression field should only be used when the normalized date fields cannot provide sufficient information.

Examples:

• Spring 1950
  • Date Expression: Spring 1950
  • Date Begin: 1950
• 1945-1947, 1982
  • Date Expression: 1945-1947, 1982
  • Date Begin: 1945
  • Date End: 1982

Undated Material

When describing undated materials, always endeavor to assign an approximate date using contextual clues and educated guessing. An approximate date that turns out to be wrong is more useful than no date, both to us and to researchers.

• Example: a set of posters protesting the Vietnam War, none carrying dates

approximately 1955-1975

• Example: a set of posters collected contemporaneous to college campus protests of the Vietnam War, none carrying dates

approximately 1965-1975

In cases where the undated material appears to be of the same era and provenance as surrounding dated materials, simply add approximately to the established date or date ranges.

• Example: folder contains correspondence dated 1964-1977, and one undated letter that appears to be of similar origins and era

approximately 1964-1977

Do not be afraid to use your knowledge of fashion, pop culture, and format to assign approximate dates to materials, especially printed ephemera and photographs.

• Example: black-and-white silver gelatin photographic prints showing young women wearing bell bottom jeans, from a baby boomer's personal papers

approximately 1965-1979

External research that can be conducted quickly and from your desktop (e.g., when were tintypes invented?) may also help assign an approximate date. However, do not spend significant time attempting to narrow a date range based on outside research. An educated guess spanning less than 50 years is the standard we are striving for in most cases.