I rollered an acrylic ground on to my zinc plate and then placed it on the hotplate until it was dry, this effectively makes it a hard ground. Without baking it can be used as a soft ground (providing textured lines with various tools). Alternatively traditional bitumen based wax grounds, both hard and soft (with different melting points) can also be used. I traced my image with a (red) carbon paper, then scratched through the surface of the ground with a needle.