Libraries and publishers have invested significantly in the creation of digitized historical collections (D-Collections). These collections include newspapers, images, and other primary sources vital to research. Portico’s D-Collection Service preserves this content on behalf of participating publishers. This service is solely supported by publishers who have committed their collections to the archive. Should a trigger event occur, access is limited to a publisher’s customers. Customers are not required to participate in Portico in order to gain access to triggered content.