Mark Rothko's painting Black On Maroon has gone back on display at the Tate Modern 18 months after it was vandalised.
Wlodzimierz Umaniec scrawled his name and the words "12 a potential piece of yellowism" on the 1958 painting in October 2012.
He was subsequently jailed for two years for the crime.
Paintings conservator at the Tate, Rachel Barker, revealed the painstaking process behind restoring the piece.
She revealed that she was only able to remove less than an inch of the ink at a time, and experienced difficulties in finding a solvent which could remove the graffiti while limiting the damage to the original painting.
Tate said the damage will always remain under the surface of the work but it had now been conserved to "displayable condition".
Tate director Sir Nicholas Serota said: "I am delighted that everyone can once again come to Tate Modern and see Rothko's magnificent Black on Maroon.
"Looking after its collection, Tate has a conservation team that is one of the best in the world. Their expertise, rigour, patient work and respect for the painting has enabled us to return it to public view, as envisaged by Mark Rothko."