I decided to try a quick portrait picture using watercolours and masking fluid.
But, since I didn't have any of this, I took the advice of a fab painter and tried to use wax. The problem is the wax I have is a tea light candle, and the wax dries very fast! The wax also clumps!
I did a quick attempt using a J.Bieber picture.. and quickly decided no more wax!!
Next one should be better.. I now have some masking fluid!! (Super thanks to Juls!!)