Generally copyright exists for fifty years after the death of the author. After that, the work enters the public domain. Works that are part of the public domain are not legally protected by copyright and can therefore be used or exploited without the consent of the owner. However, there are a few exceptions depending on the type of work involved: Joint authorship: A collaborative work is defined as a work for which the contribution of each co-author is seen an essential component of the whole. The work is perceived as a whole and consequently, is protected by a single copyright..