When I was in Switzerland in September I was able to spend a couple of hours playing with
I coated the card with white gesso first before scribbling on the crayons and gently washing over with a wet paintbrush to blend.
The white circles are where I rubbed through a stencil with a baby white.
I also created this card using the same technique but instead of white gesso I tried without gesso and on a slightly textured card.
As you can see it worked but it was harder to achieve the blended colours.