Lets call out the myth of flash photography being able to destroy an artwork. That is absolutely false. You can try it at home. The output from a flash is too insignificant to cause fading, even with a million visitors.
Prove it...
Museum conservators are responsible for the long term (as in a really, really long time) preservation and conservation of the artwork under their care. It's a well known fact that light (particularly UV) has an adverse impact on papers, pigments and materials. That has been scientifically established...
So, how much light is too much light? That's a moving target depending on the materials involved but there are standards listed here:
Limiting Light Damage From Display/ExhibitionOne statement is pretty specific: "
Light damage is cumulative and irreversible"...any light exposure causes potential damage which is why a lot of artwork such as certain kinds of photographs: salted paper prints, calotypes/talbotypes and dyes (found in colored drawing media, inks, textiles, photographs, many early chemical reproductive processes such as blueprints, dittos) are kept in dark storage and not displayed–the museum is encouraged to do a high quality reproduction and store the originals in dark storage and often in dark cold storage...
So, aside from the clear and present danger to expose artwork to excess light, exactly what sort of electronic flash would possibly be a proper light to use in a museum? On camera flash? That's clearly an inferior lighting...
I actually know a guy who works for the Chicago Art Institute and is involved in digitally archiving their collection of artwork with high resolution digital captures. The proper lighting is a challenging endeavor for sure...trying to get both color and texture and evening lighting both large and small artwork is an art in itself...and these days, much of that lightings is high CRI LED lighting since it's bright and cool (not radiant heat buildup on the artwork).
Sorry, I appreciate artwork way too much to try to get museums to do anything that might damage the artwork for generations to come. Besides, these days high ISO is pretty friggin' good!