Etching Instructional Notes

Etching

(All photography by John Beasley)

Etching is a form of intaglio printmaking. Intaglio refers to a method of printing from a plate into which recessed lines or grooves have been made. The printing ink lies in the groove below the surface of the plate where it is picked up by the paper when run at high pressure through an etching press. this differs from say, a woodcut where the ink sits on the upper surface of the plate and the cut away areas don’t print. An etching is produced by covering a metal plate, generally steel, zinc or copper with an acid resistant wax. The image is then drawn into the wax using a scriber or other tools exposing the plate underneath. The plate is then submerged in a bath of acid and the exposed lines are etched downwards by the action of the acid. The depth of these lines is dictated by the amount of time you leave the plate in the acid. There are many variations of this technique but all work by allowing the acid to only affect selected areas of the plate.

Copper etching plate and resulting print

Plate preparation

Before the plate can be etched it needs to be prepared and degreased.

1. File all four sides of the plate and round the corners, finish off with fine sandpaper for a smoother finish if you wish.

Filing the edges and corners of the plate

2. Degrease the plate by cleaning the surface thoroughly with a non-abrasive detergent, such as Cif, and allow to dry. It is also common to use a mixture of ammonia and french chalk, or a soya sauce solution.

3. Apply the ground on the hot plate with a roller (or brush if it’s a liquid ground) as evenly as you can and allow the plate time to cool down.


Grounds

There are two main types of ground; hard and soft. Hard ground is very suitable for fine, accurate lines and crosshatching made with a scriber. It cools into a dry wax coating on the plate. Soft ground always remains soft and tacky on the plate. It is useful for pressing fine textures into the plate by placing textured materials on top of the plate and passing it through the press.

Textured objects placed on a copper plate with soft ground

It can also be used to produce a soft, diffuse line by placing a piece of paper over the plate and drawing with some pressure over it to remove areas of the ground below.

Etching your plate

When you have finished your drawing, your plate is ready to be etched. It is first backed with contact or parcel tape. The plate is soaked in the acid bath for the desired time. As a general rule, heavier, firmer lines will be achieved by longer times. Etching times are generally reduced for a soft ground as the desired effects are often subtle and the ground isn’t as resilient. If using a nitric acid solution with a hard ground, it is good practice to periodically use a feather to brush away the bubbles which form on the surface for a more accurate etch. As acid is corrosive care should be taken when using it and suitable protective equipment should be used. When removing the plate from the acid bath it should be rinsed thoroughly with water before being removed from the acid room. When the plate is etched enough, remove the ground with white spirits and remove the backing. The plate is now ready to ink up and print.

Printing the plate

Cover the plate fully with ink, pushing it into the lines thoroughly with a piece of card or rubber squeegee.

Applying in on the plate

Remove the excess ink from the surface with a piece of scrim formed into a pad. Flat pieces of tissue can be used to polish the plate to make tones lighter and lines more crisp if desired. More selective polishing can be achieved by using a cotton wool bud or a fine cotton rag.


Clean off the edges and print the plate on an etching press with dampened paper.

Aquatint

This method of etching is used to produce areas of tone on your plate. It can be used in conjunction with line etching or alone. A fine layer of resin dust is fused onto the plate with a burner. When acid is allowed to etch through this layer, over time it forces the particles of resin further and further apart. The longer the plate is etched, the larger the gaps between the particles becomes and the darker the resulting print will be. When working with aquatint the tonal values of your image should be worked out in advance, as you will need to protect the plate at different stages of its tonal development, using bitumen varnish or some other acid-resistant material. Aquatint is commonly used on copper or zinc. It can also be used on steel, but as steel is a porous metal it will produce a tone when etched even without the resin layer, though the results won’t be as reliable.

The steps for producing an aquatint are;

1. Degrease the plate as usual.

2. Agitate the resin in the aquatint box by spinning the cranking handle.

3. Wait a minute or so, allowing the lumpier resin to fall. When the door of the box is opened, a fine cloud of dust should be visible.

4. Place the plate inside the box. Leave for a few minutes to ensure a decent coating.

5. Remove the plate carefully from the box so as not to disturb the resin.

6. Put the plate on the burner stand. Apply the flame from the Bunsen burner. Slowly pass the flame along, watching for changes in the colour of the resin, which indicates that the resin is melting and adhering to the plate. Do not leave the flame too long in one spot.

7. Allow to cool and remove from the burner stand.


The plate is now ready to work on. Begin by stopping out areas that you intend to be white. Use bitumen varnish, oil pastels or other suitable acid-resistant materials. Back the plate and immerse in the acid bath to achieve your lightest tone. Remove from the acid and dry. Next stop out the areas where you want only the lightest tone to remain. Put the plate in the bath until the next darkest tone is reached. Remove and stop out the areas where you want this tone to remain. Continue in this way until you have etched all tones onto the plate up to the darkest. Keep a note of how long the plate has been in the acid for in total. Usually a test strip is prepared and printed in order to judge how long the plate needs to be etched to achieve a desired level of tone.

Working out a plan for the various tones with desired times

When this process is done the plate can be printed. First remove the varnish etc. with white spirits. Then, usings methylated spirits, remove the remaining resin thoroughly. The plate can be inked up and printed as normal, taking care to wipe and polish tonal areas gently.

Spitbite

This is another form of etching generally used with an aquatint. It allows the artist to produce tonal marks that are similar to watercolour or ink washes, by painting the acid solution directly onto the plate instead of immersing it in a bath.

The tonal range available from spitbite technique

It is best to use a ferric acid solution on copper to do this, as it both gives the best results and is safest, as ferric acid is less dangerous to use than nitric.

Ferric-chloride spitbite solution

To use this technique prepare the plate exactly as above for aquatint (steps 1-7) Next, using a brush, simply paint the acid solution onto the plate and it will begin to etch immediately. It can be applied directly, or pooled into water for gentler effects. To achieve dark tones, the acid will need to be replenished on the plate several times and allowed to sit for some time. With experience you will learn to judge the levels of tone you are producing. The solution should be washed off when finished. As you are still using an acid solution, care must be taken and protective gloves should be worn to protect yourself. Before printing remember to remove the resin layer with methylated spirit.


Sugar lift

Sugar lift is a technique which allows you to  apply a solution directly to the plate and form a stencil only from the areas where you have painted it. This has the advantage of allowing you to work in the positive, as opposed to having to stop out areas of the plate which will be protected from the acid, which effectively forces you to “paint around” the areas to be etched.

The solution is made from a mixture of gum arabic into which has been dissolved a small amount of sugar, typically castor or icing sugar. Some water-based ink can be added to increase the visibility of the marks. The solution is applied to the plate with a brush or other tool and allowed to dry thoroughly. A layer of hard ground is then applied over the plate, ensuring all areas are well covered.


The plate is then immersed in a bath of very hot (almost boiling) water and this should have the effect of expanding the solution and removing the ground which is immediately over it, exposing the copper underneath.

Immersing the plate in very hot water

The bath can be agitated to remove all traces of solution for a clean result. On a copper plate, this is typically used when an aquatint has already been applied so that a full range of tone can be etched through the stencil to achieve the desired effect.

Newly formed stencil, ready to be etched with aquatint already on the plate

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