[cesther]

IANAL JALS - also may be jurisdictionally biased

There are multiple copyrights associated with most content items. You don't get copyright based on time nor the effort involved - rather it is based on originality of the work.

So you can't claim the copyright of a play by typesetting it - but by typesetting it one can have the copyright in your original typographical arrangement of that play.

So just because the underlying work is in the public domain does not mean it safe to copy a representation of it which has been created in a way which allows the person who created the representation to claim copyright over their work.

Compare a person selling a photocopied 17th century print of a book against a person who retypes the text of that book and lays it out in an original way.

IMHO the issue here is with the policies of the publicly funded museums - there is an argument that if a public funded organisation creates a new copyright work based on public domain material then they should place that new work within the public domain or at least license it using CC.