That's two reasons, not just copyright, and the millions of flashbulbs discharging there over the course of a short timespan would for sure have an effect on the lifespan of the work.
So that's a good thing for a bad reason and I totally sympathize with the position of the stewards of this amazing work.
I have a super nice story about this but I'm actually somewhat hesitant to tell it in detail in public, but I once discharged about a few 10's MW/m^2 of light concentrated on a very small part of a very famous painting.
How I got away with that will have to remain an untold story, but let's just say that my consultancy endeavours take me to interesting places and allow me to do interesting things.
So that's a good thing for a bad reason and I totally sympathize with the position of the stewards of this amazing work.
I have a super nice story about this but I'm actually somewhat hesitant to tell it in detail in public, but I once discharged about a few 10's MW/m^2 of light concentrated on a very small part of a very famous painting.
How I got away with that will have to remain an untold story, but let's just say that my consultancy endeavours take me to interesting places and allow me to do interesting things.