Even in this case it is not always true. After a certain number of years, original copyrights and all claims expire. For example, there is NO restrictions on using the original 1781 draught of the USF Confederacy from the NMM for all uses - both private and commercial. Here is an exact quote from them regarding the attached artefact. I believe it is important for all modelers to understand this!!!if it is a ship based on an Admiralty plan in any way shape or forum it is subject to licensing if it is going to be sold
The original artefact or artwork has been assessed as public domain by age, and faithful reproductions of the two dimensional work are also public domain. No permission is required for reuse for any purpose.
The text of this image record has been derived from the Royal Museums Greenwich catalogue and image metadata. Individual data and facts such as date, author and title are not copyrightable, but reuse of longer descriptive text from the catalogue may not be considered fair use. Reuse of the text must be attributed to the "National Maritime Museum, Greenwich, London" and a Creative Commons CC-BY-NC-SA-3.0 license may apply if not rewritten. Refer to Royal Museums Greenwich copyright.