A major Mark Rothko painting from the collection of the late New York financier and dealer Robert Mnuchin hammered at $74 million at Sotheby’s New York on Thursday night. With fees, it totaled $85.8 million. It’s the second-highest price ever achieved for the artist at auction. Auctioneer Oliver Barker opened the lot at $65 million, and two bidders dueled for the work for about four minutes. At around $74 million, a phone went off in the room. “Is that a new bid coming in?” Barker joked, maybe a tad hopeful. In the end, a phone bidder on the line with Helena Newman , chairman of Sotheby’s Europe, won the painting. Brown and Blacks in Reds (1957), estimated at $70 million to $100 million, was offered in an 11-lot sale dedicated to material from Mnuchin’s collection, ahead of the auction house’s main “The Now” and contemporary art evening auction. The investment banker-turned-gallerist died in December at 92.…