Programmes and films from the early days of S4C are to be kept at the National Library of Wales' screen and sound archive in Aberystwyth.
The Welsh-language channel said it would secure the collection's long-term future.
It includes Oscar-nominated films Hedd Wyn and Solomon a Gaenor, and animated productions such as the Gogs.
S4C chief executive, Arwel Ellis Owen, said it showed the style and direction the channel had taken over 30 years.
The programmes and films are currently part of S4C's own archive at its Cardiff headquarters.
"The expertise of the archive's staff in handling film is vitally important in trying to assess and preserve this collection," said Mr Ellis Owen.
"The archive's location in Aberystwyth will ensure the archive also has access to the material for research and education purposes," he added.
Mr Ellis Owen said the programmes and films showed "the style and direction" of the channel "as well as who the actors were at the time".
The National Screen and Sound Archive of Wales keeps films, television programmes, videos, sound recordings and music relating to Wales and the Welsh.
Archive manager Dafydd Pritchard said: "The archive is very glad to be working with S4C in this way to preserve these collections for the future, and eventually secure greater access to them."