Build up a variety of surfaces using whatever comes to hand that has two differently coloured layers.  Make several drawings by scratching through the second layer.  You can use wax and acrylic paint, oil glazes on board, household paint on wood, varnish on metal.  Vary the scale of drawings depending on your support.  Choose a subject from your sketchbook or learning log and push through to make complete drawings, not just squares of texture with random marks.  That way you’ll really learn what the materials can do.

This immediately made me think of the pictures children make by covering a sheet of paper with coloured wax crayon, covering it all with black crayon, then scraping off the black, usually drawing fireworks.  So that is exactly what I did first.

For my next one I was thinking that I would leave the circular area around the tree white, then have the surrounding area blue.  I had done a watercolour painting like this previously.  I used black oil pastel, instead of wax crayon to get better coverage.  Unfortunately the black oil pastel stained the white paper and scraping it only exacerbated the problem, so there is too little contrast between the black and the tree.

For my next one I used white oil pastel and light and dark blue for a kind of sky effect, again using black oil pastel.

I decided to try different media, so for the next one I covered the paper with different colours of acrylic paint.  Once dry I covered with black oils pastel and again scraped off.  This gave quite a subdued effect, as I think the black oil pastel stained the acrylic paint, but I think it gives a mysterious atmosphere to it.

Next I covered the paper with black oil pastel the painted over it with acrylic paint, then scraping the paint to draw the tree.

This worked really well, the strong colours of the acrylic contrast well with the black.

This one was done with coloured wax crayons below and white acrylic paint on top, scraped off whist still slightly wet.