The Great And Powerful Gerard, He Speaketh!
Credit as a requirement of a copyright licence only applies when a
copyright in fact exists. Restorations intended to be fidelitous do
not create a new copyright in US law. They may or may not create one
in UK law, but the question is unlikely to be resolved without an
actual case - shouting at people on a mailing list is unlikely to
influence the situation one way or the other.
What you really want is credit, and it is true that reusers should
credit the restorer in order to properly note the provenance of an
image. But you can't enforce that with a copyright that doesn't exist.
He oughta know about "shouting at people on a mailing list"--
having done it thousands of times himself.
Plus:
Per Fae's link, the sweat of the brow doctrine
has been *significantly weakened* in the UK in just the past few
months.
Sez what legal experts? Classic David, he really
doesn't think the
laws apply to him.