Carborundum is the naturally occurring mineral silicon carbide that has the beneficial property of being extremely tough. In a printing studio its often found as an abrasive used to grind lithographic stones flat. One other use however is to simply mix it with PVA glue or acrylic paint and apply it directly to any robust plate material. The carborundum areas will hold ink beautifully and give fantastic texture. Its particularly useful for colour printing where several plates each inked in a different colour and printed together.
I'm posting a few prints where I painted carborundum onto a perspex plate. The perspex areas can be wiped totally clean if desired and the carborundum areas left full of ink to give a nice high contrast image.