Distinguishing an authentic Louis Vuitton bag from a well-made fake is a subtle art that involves counting stitches, feeling the leather’s grain and poring over print patterns. A New York start-up says it has a technology that can spot counterfeits without the guesswork. Entrupy’s solution is a handheld microscope camera that lets anyone with a smartphone check a luxury accessory within minutes. Since launching the service a year ago, the company says its accuracy has improved to better than 98% for 11 brands including Louis Vuitton, Chanel and Gucci. Holographic tags, microprinting and even radio beacons woven into fabric have been used by fashion labels for years to help establish the authenticity of their products. Apparel makers will spend US$6.15 billion ($8.3 billion) on anti-counterfeit technologies in 2017, according to London- based researcher Visiongain, but the anonymity of internet shopping and the growing popularity of second-hand dealers is making the war against fakes harder. “Even 10 years ago, a woman going to buy a second-hand bag would know very well that Chanel, Gucci and Prada don’t sell on the street corner,” says Susan Scafidi, director of the Fashion Law Institute at Fordham University in New York. “But now, with so much legitimate and illegitimate commerce occurring online, it is very difficult for consumers to tell the difference.” The issue was highlighted last year when the International Anti- Counterfeiting Coalition suspended the membership of China’s biggest online retailer, Alibaba Group Holding, amid criticism that it and other e-commerce marketplaces were not doing enough to cull fakes. Alibaba founder Jack Ma did not help matters when he said Chinese-made knockoffs today can offer better quality than the genuine articles.