When a man vandalised a Rothko at the Tate Modern last month by writing on it, the gallery said they were confident they could quickly and completely repair it.
However, it now seems the damage is worse than they originally thought.
Speaking to the Today programme, the BBC's arts editor Will Gompertz explained that "[The vandal] has caused significant damage.
"There was a hope that the graffiti would wipe away, but in fact the ink from the pen has bled all the way through the canvas causing a deep wound, not a superficial graze."
"That means, because of the way Rothko worked which was building up his paintings layer after layer, they are going to have to remove the paint and then rebuild it. They reckon that whole process is going to take them a year and a half."
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