Are you looking for something fun to do with kids?
Mono printing on plaster is an exciting and magical process for all ages, and with some help even very young children can make lovely prints using this method. You can create prints like tiles that will stand up on their own, or can easily be hung on the wall. With the bright clear colours and detailed patterns, people will wonder how you made these unique tiles.
The basic kit you will need is;
- Pieces of stiff smooth plastic
You can try old file covers, plastic packaging, or plastic floor tiles. If you have a scrapstore nearby they will almost certainly have plastic you can use for printing plates. - Oil based inks and printing rollers
- Different tools to scrape the ink off
We used combs, cotton buds, kebab sticks and lolly sticks. - Strips of plastic and masking tape to make moulds
- Plaster of paris and plastic pots for mixing
First ink up your mono-printing plate
Begin with a piece of smooth plastic; this is your mono-printing plate.
Roll some oil based ink onto a smooth surface, then roll a thin layer of ink onto your printing plate.
It is important to use oil based ink for plaster printing. It cleans off with baby oil but it is a good idea to wear gloves and an apron.
The print at the top of this post had several colours at rolled onto the plate at once to make coloured stripes.
Draw a design in the ink
Experiment with different tools to ake marks in the ink. Here we are using combs, sticks, and cotton buds. Press quite hard with your wiping tools so you can see clear lines and marks in the ink.
Mono printing
This is your printing plate – there is only one design and you will make one print from it; that’s why it is called a mono print.
Mirror writing
If you want to include text in your mono print remember to write backwards on your printing plate; the final image will be reversed so if it is bakwards on your plate the writing will come out the right way round on the print.
Here is a tip
If your plate is see-through plastic you can use a dark coloured marker pen to write your words the RIGHT way round. Turn the plate over and the letters will show the WRONG way round. Roll ink on it, then you can trace over the backward letters, no problem!
For more fun with mirrors and writing have a look at this post
Make a mould
To make a round shaped plaster print, tape a strip of bendy plastic into a circle. You can also use cardboard but plastic gives your print a nice shiny edge.
Use strips of stiffer plastic or Perspex (plexiglass) for square shaped plaster prints.
The shape of your mould can be smaller than your printing plate, or the same size. In this photo the round mould is smaller than the plate and is sitting on top of it.
The square one fits neatly around the edges of the inky printing plate.
Position your mould
Lay your inky plate with the design facing upwards on old piece of board or plastic; place the mould on top of it, or butt the mould right up to the edge of the plate. Be gentle with it and take care to avoid smudging the design on the plate.
You can tape the mould down to hold it in place and avoid plaster leaking our but this is not essential. If your mould is smaller than your plate this won’t work anyway, as the ink on the plate will stop the tape from sticking.
A handy tip for rectangular moulds
A clever trick is to use the ‘log cabin’ arrangement, (as in patchwork quilts). This means that with 4 strips of plastic you can make a rectangle of any size to fit your printing plate. Fix the corners together with masking tape.
Mix your plaster of paris
Pour some clean cold water into a plastic pot. To decide how much water to use imagine the space inside your mould filled up to about 2cm deep. This is the volume. (That’s the maths for today!)
Sprinkle plaster of Paris on the water till there is a little pile showing above the surface of the water. Let it soak in till there is no dry plaster before stirring it gently with a stick. It should be like custard.
Leave to rest for a couple of minutes but no longer as it quickly start to set.
Pour the plaster into your mould
Use one hand or get a helper to hold the mould still if it isn’t stuck down; pour the plaster in carefully and slowly.
If you have made too much plaster leave it in the plastic pot to set then throw it away. If you haven’t made enough, quickly mix up another batch in a clean pot and add it to the mould before the rest has set. You will get better at guessing the volume as you make more plaster prints.
If you have any scrim or loose woven fabric you can lay strips on the wet plaster to make the finished tile stronger; push them under the surface of the plaster. You can also add loop of wire to hang the tile up on the wall if you want. Unbend a paper clip and form a U shape, push the ends into the wet plaster leaving the loop sticking out.
Leave it alone for at least half an hour to set.
Woops! the plaster is leaking out!
Don’t panic, its all part of the process, I hope you had an old board under it. You can press gently on the top edge of the mould for the first five minutes to stop too much plaster oozing out.
When it is dry the extra bits will just drop off.
Release your plaster print from the mould
You will feel the plaster getting warm and then it goes hard. This is a chemical reaction.
Don’t be in a hurry – if you take it apart too soon the image will not have transferred to the plaster. Ideally wait till the plaster has heated up and got cool, allow at least half an hour, and preferably be patient and wait an hour to be on the safe side.
After the plaster is set, peel or cut the tape from the mould and very carefully lift your plaster print off the table. Slowly peel the printing plate off the plaster to reveal your plaster print.
Break off any pieces of plaster that leaked out of the mould.
Scrape the edges of your tile with an old knife to smooth any rough bits off.
The plaster will feel quite heavy and damp, but if you leave it somewhere warm for a day or two it will turn light and dry.
So how does it work?
Plaster is made with water and the inks are made from oil so in theory this shouldn’t work; oil and water don’t mix right?
My theory is that as the plaster gets warm it softens the oily ink and as the plaster sets and dries the ink is drawn to its surface.
What do you think?
More things to try
Once it is dry you can continue developing your design if you want by scratching in to the plaster, this will make white lines in the colour.
You can use other mono printing techniques on your plate. For example roll ink on to things and press them on the plate to make interesting marks and patterns.
Here are links to other blog posts which may be helpful:
