When printing on fabrics that contain spandex or Lycra, incorporate a stretch additive to help improve the elongation properties of the ink. This will prevent the print from cracking when the fabric is stretched out. Some stretch additives can also be used as an under-base print to help improve the stretch of the inks printed on top.

Depending on the additive used, adding 5 to 10 percent (by weight) is usually sufficient for most fabrics. But also keep in mind that printing through very fine mesh counts doesn’t allow muck ink to be laid down and thus, makes it difficult to create a strong enough ink film to withstand a lot of stretch.

—Ed Branigan, International Coatings