After the black and white drawing I looked at putting a colour underlay in the drawings. This creates a layering affect as if looking through a window. However because the underneath layer is just a colour layer this means that the affect is not as strong.
This first one was just done with two layers of watercolours. The underneath layer is bright but is partially covered by the thick dark layer. However because this layer is thin and watery it is still possible to look through the dark layer to the colour. When I first produced this it was not the desired affect, although now I actually believe this is an interesting affect; contrasted with the acrylic layering, which creates a flat, dead layer atop the colourful watercolour.
These variation of thickness and opaque quality is definitely something worth playing with.