It is a process that I am not very familiar with, and, like a lot of other forms of printmaking, is very systematic and process oriented.
We tried out both hard-ground and soft-ground, and aquatint. The plates were made from copper, and we used ferric chloride which is an alkaline as opposed to an acid.
The soft-ground plate is more fragile than the hard-ground, and one needs to draw on the plate on the same day as the ground is put on (unlike hard-ground which can be left for years before being drawn onto).
Soft-ground produces softer lines, and picks up the texture from fingerprints, lace, feathers etc. I experimented with scrunching up paper and pressing different shapes cut of of card onto the plate. I also pressed rubber bands into the ground.