公有領域
→Public Domain
Public Domain Image Archive
https://www.youtube.com/watch?v=PMp_-OX15Jc
2023-01-01 Sherlock Holmes Enters The Public Domain — Here Are The Other Works Free To Use In 2023
Copyright expiration extends to works that have been lost, including 75% of American silent films, according to the Library of Congress. Jennifer Jenkins, director of Duke University’s Center for the Study of the Public Domain, said extended copyright terms have “contributed to the loss of our cinematic heritage” because some older works have since disintegrated and have been lost to time, preventing their preservation.
當然也很難說這75%的失傳作品全都具有價值或需求
2013-06-10 70年代以前のNHKドラマがもう残ってない件 - Togetter
2023-07-11 過去に登場したゲームの87％はもう遊ぶことができなくなっている - GIGAZINE
2020-06-01 本の虫: パブリックドメインの漫画が出てくるのは2050年代から、アニメは2030年代から