This is one technique that seems to be popular amongst many German illustrators and artists. I remember doing this in Primary school and since then haven't thought of using this but the effect seems quite effective. Please see...
This is by Henning Wagenbreth. I think he has then taken the artwork and set to coloured backgrounds done on the computer.
To make scraper board you need,
Scraperboard is a sandwich of stiff backboard, hard white china clay and a surface of indian ink. You can buy it ready made but this is not so easy these days so you can make it instead quite easily. You need
- backboard or mount board
Mix glue, chalk and pigment and paint onto board in several thin layers, letting it dry in between recoating. Then apply several layers of indian ink, letting it dry in between again. Then just scratch and scrape to create!