Archival reproduction combines durable inks, acid-free paper, acid-free mounting and framing (usually behind glass), and proper storage away from UV light sources -- particularly sunlight. The absence of any one can diminish longevity.
Archival paper is an especially permanent, durable acid-free paper. Archival paper is meant to be used for publications of high legal, historical, or significant value. In the USA, such paper must also be approved by the ANSI standards. The international standard for "permanent" paper is ISO 9706.
Reactive Imaging uses archival quality inks and offers optional acid-free paper and mounting boards.