Some of the 3M reflective striping is all but unprintable. I tried a dozen or so ink types on it, from plastisols with and without additives, vinyl inks, and several catalyzed specialty inks. I seem to remember 3M offered an ink that was said to work, but it would have been several hundred dollars and many weeks for me to get a quart in to try and the job wasn't worth the hassle. We don't run into many substrates that baffle us as but this was one of them. Tomorrow I get to try some inks on some specialty stretch material for Olympic speed skating suits.