Gouache has been around a long time. But it has never been very popular - until now. Its trendiness comes from an unusual direction - from the dawn of digital illustration, actually. Adobe Illustrator software creates shape-based images with flat color fields, and this look became a style in magazine illustration because, as publishing went digital, it was easier to work with illustration that was already digital. Now the look is ubiquitous. You hardly see any other illustration style in any art or lifestyle magazine. Analog illustrators had to attend to the trend with real world art supplies.