Acrylic Resist Etching<techniques
Acrylic Resists
It is a well established fact that the conventional materials for intaglio printmaking contain quite a cocktail of acids and chemicals, the danger of which is unmatched in the creative arts. Each of them may have damaging effects on the health of the artists and on the surrounding environment, but in combination they pose a very serious threat to anyone who uses them with some frequency.
(Henrik Boegh – Handbook of Non – Toxic Intaglio)
By using acrylic resists – which use water as solvents, water based inks and vegetable oil and washing soda as cleaners together with ferric chloride (a salt) instead of nitric or sulphuric acid these toxins can be avoided and the health and safety of the printmaker and the environment can be assured.
Plate Preparation
Filing the Plate
The first stage is to file a 45º bevel edge onto the plate to allow easier inking and to protect the press blankets. This also helps the hard ground to stick around the edges of the plate
De-Greasing
It is vital that the plate be thoroughly de-greased to allow the acrylic resist to adhere properly.
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Sand with fine wet and dry
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Clean plate with liquid household cleaner and rinse (or use chalk powder and water)
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De-grease using Soy sauce
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Rinse
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Dry
Liquid Hard Ground
Acrylic floor polish is used as a hard ground, this is extremely strong and the plate can be inked and printed with the ground still on. It is worked in exactly the same way as a traditional hard ground but can also be washed with a mild solution of ammonia and water. A thin even coating is essential otherwise the ground may break up during etching. A little copolymer binder is added to the polish for extra strength.
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Hold the plate above a tray and pour on a liberal amount of polish in one go.
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Distribute it quickly before it has time to dry and place vertically on newspaper or cloth to allow run off of excess.
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Move the plate a few times to avoid a build up along one edge.
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Leave to dry or use drying cupboard. (approx 10 mins)
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If you prefer a black surface to work on paint a diluted gouache over the plate and allow to dry. This must be removed in warm water and detergent before being etched so it doesn’t ruin the ferric chloride.
Etching
Etching takes place in a vertical etching tank using the Edinburgh Etch, a mixture of Ferric Chloride and citric acid.
Backing the Plate
Before etching the back of the plate needs to be protected.
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Cover the back with packing tape.
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Trim edges.
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Make a handle for lowering in and out of ferric chloride.
Etching
1. Hang the plate in the etching tank and peg handle securely.
2. Make a note of the time the plate went in.
3. The timing depends on a number of factors – the age and strength of the ferric chloride and the temperature can affect the speed of the etch. If the mixture is used infrequently it may be necessary to kick start it by putting in a scrap of copper 3-4 hours before using. As printing can take place without removing the ground you can always print at intervals until the desired depth is reached. An etching could be achieved from anything from a half to two hours.
Areas may be stopped out during etching to give various depths of line.
Stripping
Remove as much of the tape from the back of the plate as possible.
Acrylic grounds can be removed in a mild solution of soda crystals. This also removes any left over tape from the back of the plate.
If time is pressing ground can be removed with caustic soda but extreme care should be taken if using this method.
Printing
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Apply ink to the whole plate with a piece of card.
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Remove excess ink with card.
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Wipe with newsprint (old telephone books)
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Print on dampened paper – time of soaking depends on type of paper.
Akua Intaglio inks can also be used on dry paper.
Plates can be proofed with hard ground still on – or if preferred left on the plate.
