Sad on many levels. The yellows were so strong and achieved Vincent's brightness goal ... to have them fade now robs of us his intent and result. Nothing lasts forever, it's true, but with the professional care of the Van Gogh Museum in the Netherlands, one would have hoped they'd last a lot longer. Not to fault them, however. I'm sure the finding by the chemists was not welcome news. Now the museum must display Sunflowers in darker settings, or commission someone to figure out an antidote.
To see Sunflowers anywhere but in a bright setting robs them of their power.
The Boston Globe is one of many news outlets to carry the story, but I do not agree that the browning of Vincent's most powerful works is "weirdly appropriate" as Josh Rothman states:
It's definitely sad that the paintings are fading, but you can't deny that it's weirdly appropriate, too: The sun is fading the painted sunflowers, just as it faded the real ones.
It is another tragic event in a life already fraught with tragedy.
Vincent had his brown period of painting while in the North. When he came to France, his works exploded with color. Such were his techniques and manner until his final days, if he'd wanted to return to brown, he'd have done so.
I'll also add this, it is Vincent's powerful manipulation of color that made him, posthumously though it was. If he'd stayed with browns and greys, he would not have gained global status as an artist.