I used some sharpie enamel paint markers to put a koi on my bag. A couple of the colors (blue, and green) never quite dried completely, so I ended up having to go over it with clear krylon to seal it. I did it last august and it has seen daily use. Its held up fairly well, not quite as vibrant as new. I used some regular sharpie markers on an old bag and after a few rides in rain and sun it was more stained than colored. go figure.