This is a technique from Design matters TV. It is basically a resist method. Using oil pastels you scribble on a page - you can see my turquoise sample at the top of my sketchbook. You then place this face down onto your paper and use either a stencil or a picture and trace over it with a standard pencil. The oil pastel paper can be reused several times. You can see i have done a quick outline of a bird and some circles. Now for the interesting part. using water colours you can paint the picture and the water colour will not go beyond the oil pastel lines. - yet to do that bit!!!