I am using indian ink and watercolor ink on yupo paper, I just wanted to know if they need to be seal or I can leave it like that. If it needs to be seal, could ypu recommend a product that I can buy in Europe, thank you!

We highly recommend you protect your work on YUPO to not only protect your painting from harmful UV light, but also to seal the paints to the surface. In Europe you can buy the Lascaux Fixativ, and we believe the Krylon Crystal Clear can also be purchased in many EU countries.