Paste & Paint.

 About a week ago I was playing with a medium made of cornflour, glue and other ingredients to make a thick type of modelling paste that can be coloured and painted onto heavy paper.
http://mycamerandme.blogspot.com.au/2016_03_01_archive.html

 The idea is to sculpt the surface with stamps or anything else to give it texture. After the paper  dries over night, it can be ironed flat (it curls as it dries) and further embellished with rubbed oil sticks or more stamps.

Here I've used a spiral stamp.

 

This is one where I've inverted the colours in Photoshop.

 I think the image now looks like waves and a choppy sea!