The palette I use for my paints is a piece of panelboard, 18 x 23.5 inches. It probably came from a hardware store. In school, at ten years old, I was taught wet on wet watercolor. We used these panelboards as easels for the wet paper. In seventh grade I took one home for calligraphy homework and never returned it, which proved to be helpful when I returned to watercolor as an adult. It isn't very portable, but I like to carry things with me.