There are six basic methods of printmaking: monoprint, relief, intaglio, screenprinting, lithography and digital. Each method allows completely different qualities and possibilities. Some can be hand printed but I usually use a printing press.
All require the printmaker to first make a plate, which will be inked up before the image is transferred to another surface; in my case, paper.
This is why they are unique, original prints - they are not reproductions.
The printmaking techniques that I have used in the work featured on my site are:
I use drypoint and etching. Usually the first on plastic and the latter on zinc.
With drypoint lines are scraped into the surface and these receive the ink and print; they produce soft blurred lines because the material is displaced into a 'burr' rather than being removed.
For etching the image is 'bitten' into the plate by acid or corrosive salt and produces a clean line as a result.
This is the opposite of the intaglio methods. I work with lino and wood. The surface is cut into; when inked up the marks below the surface remain clean and do not print. Think of potato printing as a child!
One starts by in effect making a collage. The sky's the limit in materials used as long as they are not metal (which could damage the roller on the press). I use PVA glue to stick them down on card or board. Once dry I use ordinary matt varnish to seal the plate on both sides. This creates a relief block which is inked-up like an intaglio plate.
This is a very brief note on what are complex techniques.
There are many excellent printmaking books, I like the Printmaking Handbook series produced by A&C Black, London.
You can also find out a lot more on Wikipedia!