Since I first started scratchboard I have always used Ampersand Claybord which is a masonite board covered with white Kaolin clay and this is then covered with India Ink.
Scratch art is a form of etching which is done by scratching lines and dots with the white areas being achieved by removing the black ink to show the white clay underneath; and for the very dark shading, the black is left as is. There are a number of tools that can be used for scratching such as a craft knife that has a number of different blades that come with it and which can be purchased at the dollar stores
Animals are an ideal subject for this medium, although landscapes, portraits and still life can also be done using this method.
Scratch art is quite unforgiving if a mistake is made during the progress of your work, however minor mistakes can be corrected by painting over the area with Ampersand Black Repair Ink and then re-scratching.