Some photographs are artistic and obviously should be copyrighted, and it might be difficult to determine where the line is, but these museum photographs are definitely not intended to be creative, to be "derivative works" the way a folk song arrangement might be.
I was reminded of this last Sunday when my church observed St. Francis' Day with a blessing of the animals, and the music included a four-hands version of part of Saint-Saëns' Carnival of the Animals. The movement "Tortoises" in Carnival is a slow-motion version of the Can-Can from Offenbach's Orpheus in the Underworld, a very popular and familiar tune at the time. The obvious symbolism is that the tortoises are dancing, albeit very slowly. ("The Elephant" is a similar reworking of an existing theme.)
Yet if modern copyright laws had been in effect then, Saint-Saëns wouldn't have been able to create his "derivative work." Offenbach's publisher would have sued the pants off him. I'm waiting to hear an argument why we'd all be better off if Saint-Saëns had been prevented from creating Carnival of the Animals. Of course I'm not arguing against copyright in general, just that its term is far too long. Offenbach put on hundreds of performances of Orpheus in the first few years, and the work was thirty years old by the time Saint-Saëns created his masterpiece. Surely Offenbach had gotten as much financial reward as he could realistically expect (not to mention he had been dead for some years).
At least Saint-Saëns didn't turn around and insist that his derivative piece should enjoy copyright in perpetuity, the ultimate hypocrisy being perpetrated by Walt Disney and other movie studios, who have made billions from derivative works of Hans Christian Andersen, Rudyard Kipling, A.A. Milne, Lewis Carroll, et al., and now want to prevent others from doing the same.
John Howell says
In general, Offenbach’s parodistic technique was simply to play the original music in unexpected and incongruous circumstances.”
John