I love Frixion pens. Today, I traced a design for Redwork embroidery using a black pen. After tracing, I ironed on sheer interfacing. A few minutes in the freezer and my design was back. The design will be covered by the embroidery so I am not worried about the ink coming back again. I use the pens in marking my quilting designs because I like the fine line of the Frixion pens. I've never had a problem with the pens.