Re: Water Soluble Wax Crayon over Oil?
Cold wax medium can be used alongside oils, so the Neocolors might work. I think that water might not be a good idea. You could try contacting Caran d'ache, they have always been quite good at answering questions that I put to them.
"I am not yet born; provide me, with water to dandle me, grass to grow for me, trees to talk to me, sky to sing to me, birds and a white light in the back of my mind to guide me."
From Prayer Before Birth by Louis Macneice.