Techniques - Print Making
Hard Ground (using a Copper Plate)
This is a type of intaglio print (intaglio is when the image is incised into a surface and the incised line/sunken area holds the ink and is therefore the section that will be printed). This is the opposite to relief print (relief is when the image is raised due to the cutting or etching of a printing surface in such a way so that all that remains of the original surface is the design to be printed and this is the area that holds the ink eg Linocut).
In hard ground print making, the plate is covered with an acid-resistant coating and then a needle tool is used to draw lines into the plate - thus exposing the metal. The plate is then submersed into an acid tank (usually ferric chloride for copper plates, and nitric acid for zinc plates). The exposed lines on the plate are then bitten away in the acid while the rest of the plate is protected by the acid-resistant coating. After etching onto the plate, ink is then wiped into the etched areas of the plate and and it may be printed onto damp paper under pressure (such as a presser). The etched lines holding the ink will then print onto the paper.
1. You will require a copper plate (the plate is cut to size).
2. File the edges of the copper plate using a file to remove any burrs on the edges of copper.
3. Place self adhesive plastic or acrylic varnish on the back of the plate if you wish to protect the back of it.
4. Thoroughly clean the plate to remove traces of grease. Rinse both the front and back of the plate in water.
Use Chlorine cleanser on an abrasive sponge / wire brush / fine steel wool / wet number 600 emery paper / corundum paper to clean the plate.
5. Dry thoroughly (eg with a hairdryer or paper) ensuring no dust remains on the plate.
6. Cover plate with an acid resistant coating. A brayer can be used to ensure a thin even layer of ink.
An acid resistant coating is made of asphaltum, rosin and beeswax to varying degrees depending on whether it is of the ball or liquid variety. For example, you could use enamel paint, water proof ink or wax.
7. Let dry (eg with a hairdryer).
8. Once the resist is dry, a sharp metal point is used to draw into the plate - ensure that you have scratched through the layer of resist. Etching tools used are, for example, gouges and blade heads of a U or V shape.
9. With gloves on, use chemical to bite the lines into the plate. Do this by placing the plate into a vertical dip tank with the chemical in the tank. The strength of the acid will affect the length that it takes to etch.
Chemicals: Ferric chloride may be used for etching copper or zinc plates, whereas nitric acid may be used for etching zinc or steel plates. Typical solutions are 2 parts FeCl3 to 2 parts water and 1 part nitric to 3 parts water.
10. Wash the plate with water.
Depending on the resistant used, you will need the following to remove the resist:
Water to remove water-soluble ink resistant
Alcohol for inks insoluble in water
Turpentine to remove paint or varnish
Acetone if used nail polish
Alcohol (methyl hydrate) or steel wool for wax-like grounds.
11. Use a scraper (eg piece of lino or cardboard) to ink your plate. Ink your plate by spreading the ink on with your scraper.
The ink used is an etching ink and is similar to oil paint. Water based etching inks are available for etching but a lot of people still like to use traditional oil based ink. Oil or other additives can be added to make ink less stiff & easier to use.
12. Wipe off the ink (using, for example, a flat pad of scrim/muslim light material cloth or newspaper) so that the ink just remains in the bitten sections of the steel plate. Use firm but gentle strokes and wipe from all angles to ensure that all angles contain ink fills within the etched lines. Finally, for a bright clean print, use tissue and wipe it on the plate by holding it flat against the plate. Your plate is now ready to go through the press rollers.
13. You will require paper to create your print from the plate. Good cotton paper is normally used for etching eg fabriano 285gms. Soak the paper in water (eg using a water tray) to ensure that it is soft & viable making it easier to be forced into etched lines during printing.
14. After you soak the paper in water you will need to blot it to make sure that it's not too wet and that any dust or moisture is brushed off. One option of how to do this would be to place the damp sheet in between two dry sheets and rub over the top to remove the excess water. When picking up the damp sheet, make sure not to smudge or dirty it with your hand. A good idea is to use a small piece of cardboard with your hands to ensure your fingers don't touch the page.
15. 'Bed' the plate for putting it through the press rollers. To do this, place some sheets of paper/newspaper under your etched plate (plate facing up). It is a good idea to mark the top sheet of the bed with the outline measurements of your plate to ensure that it is correctly placed for running through the press rollers.
16. Place your blotted paper on top of the etched plate. Place some tissue paper over this and then the press blanket is finally placed over all of the 'bed'. It is now ready to go through press rollers.
17. Run it through press rollers.
18. Gently pull the paper off.
19. Leave the print to dry.
A very quick overview of this process can be watched here. More detailed videos may also be found on youtube.
Different tones may be achieved by painting out areas with acrylic varnish as the plate is being etched. The acrylic varnish is used on the back of the plate to protect it (see step 3 above) but this can similarly be used on the front of the plate, where you are etching, if you wish to block out any areas on the print.
A simplified version of a hard ground technique can also be prepared, for example, by using acetate paper (see below)
USING ACETATE PAPER
This is a technique similar to the hard ground technique described above except, instead of using a steel plate to prepare our print on, we are this time using acetate paper. A sharp needle tool is used to create a drawing on the acetate paper. You will then ink it, bed it for the print press, place it against damp paper for the ink transfer and then, finally, run it through the print press.