Substrate Options —‘Paper or Plastic?’

Apart from getting the right ink to adhere to a given substrate, plastic printers are also faced with getting the ink to dry. "Conventional inks are designed to oxidize on paper; on nonporous plastic, the ink just sits there," Reis explains. And while ink and water balance has to be right to print decently on both paper and plastic, the fact remains that paper absorbs water, while most plastics won't. This means less water in the fountain solution, and the use of inks that will perform well with minimal water in the feed and press. According to Tenyer, this is something with which inexperienced press operators have a hard time adjusting.