Can water create a boundary for paint washes?

In real watercolor work, if you paint an area with plain water and then add a little paint, the paint will only spread to the boundary of the original wet area.  It won't bleed onto the dry area.  Is this possible in Fresco without using a mask?  Also, is it possible to see an area where you have painted only plain water?  On real paper it is shiny, but I cannot see anything at all on the Fresco paper.  (These may be feature requests, or I may misunderstand how Fresco works.)