In troubled times, there’s something about Mark Rothko’s art that provides respite. His iconic rectangular colour fields – vibrant empty spaces, layered with texture – absorb our focus and allow our feelings to meander in oddly reassuring ways. Perhaps this is why Rothko is having such a resurgence in Europe right now. Last year, the Louis Vuitton Foundation presented the first retrospective in France dedicated to his works since 1999. Now, it’s Norway’s turn: a fascinating new exhibition dedicated to the 20th century abstract artist’s lesser-known works on paper opens at the National Museum i…