I made my daughter a signature quilt for her wedding and after much research, I used these pens that I found on Amazon
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1. I even contacted the company before my purchase to explain how the pens would be used to make sure they would work. I was assured that they would. I washed the muslin first and after all the signature blocks were gathered, I ironed all the signature squares. After the quilt was done, I washed and dried the quilt and had no fading or smearing. I can't give a test of time because her wedding was last June. But she treasures that quilt and so I don't see it being washed and dried so much in it's lifetime. The pens come with a fine tip and and a thick tip so I taped over the cap end on thick end so it would not get used. Hope this helps you a bit.