Public domain refers to a state in which a work, text, or name is not protected by copyright or trademark rights, or is otherwise outside the scope of such protection. In the provided context, this term is invoked in relation to BNE’s work BNE Water Foundation. For the exhibition, the organizers attempted to contact BNE Water Foundation domestically and internationally, but were unable to do so. They then confirmed, with the cooperation of specialist institutions, that text made only with the Helvetica font is not recognized as a copyrighted work under Japanese copyright law, and that “BNE” is not registered as a trademark in Japan. Based on this verification, the work is presented while expressing respect for the anonymous artist.
Within this context, public domain is not explained as a broad legal category with detailed rules such as expiration of copyright terms. Rather, it functions as a practical condition for presenting material when rights protection cannot be established or does not apply. The passage highlights how curatorial and legal checks can determine whether a name or text may be shown without infringing rights.