We are going to let some people sign a banner (slogan) and then hang it outside. How can we ensure that it doesn't fade when it rains or for a long time?

1. You can press a layer of plastic film on it after signing your name like a photo is plain. This printing shop should have

2. Sign your name directly in the sign-in book, and then print it on your banner in the printing shop.

3. Simply change the paint pen. Textile pigment is the best choice, followed by propylene, which is available in general printing materials stores and will not fade.

All the above are personal thoughts, because I haven't really done it myself. I don't know if it can achieve the desired effect. You can also ask the people in the printing material store to see if they can solve it.