Printpack will debut a new way for brands to interact and engage with consumers at this year’s PACK EXPO Las Vegas. The technology – utilizing a proprietary process invented by Printpack – allows for photochromic ink to be hidden within standard graphics and remain invisible until exposed to sunlight.   The process represents the first time photochromic ink has been applied to a flexible film, giving brand owners in any market capable of utilizing flexible packaging new options for interactin...