United States Department of Defense | United States Department of State | United States Department of Justice | United States Department of Agriculture | United States Department of Energy | United States Department of War | United States Department of Veterans Affairs | United States Department of the Treasury | War Department | Secretary of State for Foreign and Commonwealth Affairs | Los Angeles Police Department | United States Department of Transportation | Beni Department | Department of Energy | United States Department of Labor | Cochabamba Department | United States Department of Health and Human Services | United States Department of Education | Antioquia Department | United States Department of the Interior | United States Department of Housing and Urban Development | United States Department of Homeland Security | New York City Fire Department | Department of Transportation | Department for Transport | Chicago Police Department | Bureau of Indian Affairs | New York City Police Department | Family Affairs | Department for Environment, Food and Rural Affairs |
Pratt's photographs are in various private, public and corporate collections including the Ford Motor Company of Canada's Photographic Collection at the Canadian Museum of Contemporary Photography, The Department of External Affairs in Ottawa and the Art Gallery of Nova Scotia.
In 1958, he joined the Department of External Affairs and served in Geneva, New Delhi, Washington, and Ottawa.