Lithography works on the fact that grease and water repels each other.
I think a good way of explaining it is if you ever have a drop butter or oil in your
kitchen and try to remove it with water, you know how the
water just kind of falls on the edges of the grease.
That's basically what makes lithography work.
With lithography you print traditionally from a lithography stone, which is a
special kind of limestone that is taken from one quarry in Germany.
The first step of the process is that you want to grain and level the stone so it's completely
level and you have a fine grit on it that you can draw on.
When you start your drawing you use a
lithography crayon that has a grease content in them or a tusche wash.
You draw this on the stone and the artists create their artwork.
When the drawing is done you start to process the stone to prepare it for printing.
The first step of processing your stone and preparing it for
printing is called the 'first etch'.
What we want to do is to start the chemical process that
prepares your stone to be printed.
After you draw on your image the stone is
still sensitive to grease and we need to desensitise the stone.
By using gum arabic and nitric acid we will be starting the chemical process.
You apply the gum arabic onto the stone, which together with the limestone
creates a layer that we call 'absorbed gum layer'.
The gum arabic and the nitric acid will together help the grease
from the drawing material get penetrated into
the stone and create a greasy reservoir directly underneath your drawing.
This is what your printmaking ink will hold onto because grease and grease attract each other.
After you've done your first etch you want you stone to rest for at
least an hour so that the grease can settle into it.
After you've been waiting and the stone has been resting we are going to start the
second part of the processing of the stone, which is to wash out the drawing
materials and replace them with the printmaking ink.
In lithography we use a special printmaking ink.
The first step to do when you wash out your drawing is to
use turpentine to literally wash up and remove the drawing from the stone.
At this point you can only see a ghost image of the drawing you made and this
is the grease that has penetrated into the stone from the first etch.
After that you want to buff in a bit of the printmaking ink onto this stone and let
the stone rest for about five minutes.
After that we will be using a leather roller to roll up the stone
with printmaking ink.
We sponge on the surface of
the stone and create a thin layer of water and this is when the absorbed gum
layer is helping to hold on to the water.
After you sponge you want to
straightaway roll with the printmaking ink onto the stone, which will
attract the grease that is already in the stone and you can see your image
building up again.
After you have rolled off your stone it's time to do the
second etch. The second etch helps to really establish the absorbed gum layer,
to make sure that the stone is not sensitive to grease anymore.
The second etch works in the same way as the first etch, you apply gum arabic onto the
stone and you also apply gum arabic mixed with nitric acid onto the stone.
After you've done your second etch, you want your stone to rest for at
least an hour, but then after the stone has been resting you can start printing your stone.
To print your stone you need to have a special lithography press, you place your
stone on the press and you adjust the pressure for that stone
because all stones have got different thickness.
Then you want to wash out the ink
that you have on the stone you use turps (turpentine) to wash it out.
Buff in the ink you will be printing with and then you roll up the stone in
the same way as you do when you're rolling up to prepare it for the second etch.
When you get the right blackness on the stone you can start pulling prints
Between every paper you need to re-ink your stone and when your print starts
to get grey you need to add more into your roll as well.