OK Angela - I have the answer for you. If the markers bleed into the fabric, I think you will find that it is not the most waterproof of umbrellas. What you could do is waterproof it (you can get spray cans from Millets, etc.) and then try the markers. I am sure it will work. Then you will not only have a fantastic-looking umbrella but one that keeps you dry, too which I think could catch on!:D