Tate Modern visitor Tim Wright snapped this photo of a Mark Rothko painting that was tagged by the co-founder of a controversial movement. ((@WrightTG/Tim Wright/Twitter)

A Polish man has received a jail sentence of two years for defacing a Mark Rothko painting at the Tate Modern gallery in London.

Wlodzimierz Umaniec, also known as Vladimir Umanets, had entered a guilty plea to criminal damage of property valued at more than £5,000 ($7,900 Cdn) in a London court.

Tate Modern officials estimate it could take up to 20 months to repair the Rothko painting Black on Maroon, which Umaniec defaced during gallery visiting hours on Oct. 7.

Restoring the abstract work could cost upwards of $318,000 because the paint Umaniec used has seeped through Rothko’s layers into the canvas level.

Umaniec, 26, who lives in Worthing, West Sussex, stepped over a barrier in the gallery and daubed the words “Vladimir Umanets, a potential piece of yellowism" on the painting before escaping.

The day after his attack, he defended his actions, saying he was a co-founder of the “yellowism” movement and had improved the value of the painting with his addition because it created a new work of art.

At Inner London Crown Court, Judge Roger Chapple reproached Umaniec, saying he had defaced an artwork that had been a gift to the nation and that his act was “deliberate, planned and intentional."

American abstract artist Rothko donated Black On Maroon to the Tate in 1969.

Umaniec was "plainly an intelligent man," the judge said, but added that the actions were “unacceptable” before issuing the two-year jail term sentence.

Auction house Sotheby's has valued Black on Maroon at $8-14 million.