This artwork was painted with gouache which is like an opaque, slightly more matte version of watercolour. This means that like watercolour, if the artwork comes into contact with water, the dry paint will 're-wet' so you should frame it.
Painted on high quality 100% cotton Saunders and Waterford watercolour paper with deckled edges. Deckled edges look quite nice when your framer 'floats' the artwork in a frame. Or you can of use a matt board as a border.