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Whelan concurs. “The thicker you can put down the ink, the better response you get,” she says. “Thinner ink film does not give the dramatic effects typically desired. And screen applications tend to provide the best results. Converters should understand that double bumping might be necessary.”

Shearing is also an issue. Duncan explains that many thermochromic pigments/dyes are microencapsulated, and will not stand up to very high shear conditions. Printing conditions where doctor blades are used can, over time, crush encapsulated particles creating a color change. “Therefore, it is recommended that inks get to the substrate with a minimum of recycling through pumps, mixers, and under doctor blades,” he says.