WHAT IS AN ETCHING?  A GUIDE TO ETCHINGS AND THE ETCHING PROCESS
Etchings using hard ground, soft ground, copper plates and acid, an etching press, paper and ink.

COLIN BAILEY
ARTIST & PRINTMAKER
Etchings and the etching process explained.
Part 1
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Etching is a form of printing that along with engraving comes under the category of Intaglio. Images printed (etchings) by this process are the result of ink being forced out of the incised lines in a zinc or copper plate using a heavy press. This results  in  slightly raised ink  on the paper and a characteristic plate mark showing the edges of the plate
Others categories are:
Relief:
The image is printed from the raised areas with non printed areas cut away - woodcut
Planographic:
The image is printed from the same surface as the non printed areas - Lithography
Stencil:
The image is printed by ink passing through areas cut away from a stencil - Serigraphy, better known as screen-printing or silkscreen
Ink jet:
The most recent development,  ink is sprayed onto the printing surface. The most basic example being the standard home printer and the commercial application being  the high end Giclee printer. What is a Giclee print?
Traditional etching press with starwheel
HISTORY OF ETCHING
The techniques of etching and engraving are believed to have originated in Medieval times as a means of decorating armour and metal. The incised lines would have often been filled to darken them and from this it would have been a short step to transferring the image to cloth or paper. One suggestion is knights falling on soft ground would have left an impression of the patterns on their armour.
Etching differs from engraving mainly in that acid does the work of removing the metal. This allows a fluidity of mark and in the hands of an expert a almost infinite degree of control; The depth of each line can be controlled by the acid and so can hold as much or as little ink as is required to achieve the desired tone. Most metals can be used for the etching plate although the most common are Zinc and copper. Zinc is often used as a starter metal for students as it is relatively cheap and easy to work. Copper is much denser and less brittle and will yield more prints. It can also be steel-faced to last almost indefinitely.
The two etching techniques I employ are Hard Ground (the most basic form of etching) and Soft Ground. I rarely use aquatint. The techniques I describe here are traditional methods adapted and modified to a modern domestic environment. Virtually everything apart from the printing can be done at home with suitable care and little space. The modern table top press is now capable of printing etchings that match those done on heavy studio press (at least for small plates) and so there is now no reason why even the printing cannot be done at home!
Giovanni Battista Piranesi - example of etching
PREPARING THE ETCHING PLATE
I use 16 gauge copper plate (1/16th inch) which comes in 500 mm x 1000 mm sheets polished on one side and covered with a plastic protective sheet. This I cut up (very carefully!) by scoring into it over 50 times with a heavy craft knife and then snapping it away. This may sound a little brutal but I have not had a lot of luck with guillotined plates - however sharp the blade there nearly always seems to be a slight bending or compression of the metal which is almost impossible to straighten and which causes the prints to fade away at that edge. Most of us don't have a heavy duty guillotine lying around the house and trusting this to others can result in scratches and plates that vary in size and are not perfectly square. I have experimented with three plate colour etchings in the past and this can make the plates difficult to register. Before removing the plastic coating I roughly bevel the edges of the plate to a 45' angle using a coarse file. This is optional but I find it much easier to roll the plate - with less chance of the roller catching the edge. When the print is finally ready to edition I finish off this bevelling with fine sandpaper and polish it up with the back of a spoon which gives a sharp clean print mark that does not cut the paper. Bevelling the plate before printing is compulsory in any class I teach! I have seen too many expensive blankets sliced through by the edge of an un bevelled plate
Copper sheets from printmaking suppliers come with a protective sheet covering the polished front surface (not to be confused with zinc Jetplate which has a tough acid resistant coating on the back). I would advise keeping this on as long as possible (regard it like the protective plastic they put on mobile phones or new laptops/tvs). After removing the plastic coating I clean the adhesive residue off with white spirit and check for scratches. If the copper plate has tarnished I polish it with Brasso.
Before laying the ground on I degrease the plate. Traditionally this would have been ammonia and chalk but in a domestic situation a combination of washing powder and soda crystals dissolved in hot water works as a substitute (be careful to dissolve the powder and crystals thoroughly first and use a soft sponge to scrub the plate). Cream cleaners such as Jif (Now unfortunately renamed Cif!) used to be perfect as they contained ammonia but in our health and safety conscious times this has been changed and they just don't work as well. Recently I have discovered that Mr Muscle Kitchen cleaner is an admirable degreaser!
For heating the plate I use an ordinary domestic cooker (Gas is better, but with a bit of practice an electric ring is just as good. Manoeuvre the plate with a metal spatula so it is heated evenly and place it on a flat smooth heat resistant surface (this will get ground on it so check it can be cleaned with white spirit!)
Charles Méryon
(1821 - 1868),
Giovanni Battista Piranesi - example of etching
Rolling hard ground onto a heated copper plate for etching
In etching, the plate is covered by a ground, or "resist" which protects the plate from the acid and is then drawn into with a needle.. Ground usually comes in the form of a wax ball which is melted onto a heated plate and then spread evenly and thinly with a roller. The Ground can either be hard - for fine, precise lines or soft - the wax doesn't set; any textured object pressed into it will pull the wax off when removed exposing the plate. Placing paper over soft ground and drawing on it will create marks similar to a hard pencil.
Detail of Watchbell Street etching - plate just prior to being bitten in acid, exposed copper showing through the smoked hard ground
Drawing into the smoked hard ground with a etching needle to expose the copper plate
HARD GROUND ETCHING
If you have used the roller recently and it has been kept wrapped in a plastic bag you will probably have enough ground already on the roller. Otherwise draw on the hot plate with the ball of hard ground - about enough to sign your initials 1 inch high is usually enough for medium size plate. The ball should skid across the plate without dragging. Roll the ground until it is even and the plate looks as though it has been coated with golden syrup (thicker than this and it will chip or make finer lines bite unevenly. You may well need to re-heat and re-roll the plate several times. Use the roller in a swooping motion in one direction to pick up the ground, and backwards and forwards to load more ground on to the plate. As the ground cools it will become sticky and hard to keep even. When reheating the plate be careful to remove it just as the ground starts smoking as further heating will cause the ground to scorch and become porous to the acid.
Obviously having a ground the colour of Golden syrup an a copper plate is not going to be that easy to draw on! The ground will be a matt non reflective finish when cooled and the copper will be shiny but I would still advise smoking the plate.
SMOKING THE ETCHING PLATE
Smoking darkens the wax ground to a black finish by letting it absorb carbon from a bundle of burning tapers. This involves clamping the plate on one edge with a pair of swan necked adjustable pliers (protect the surface of the plate with a small piece of folded card) and holding it above your head with the grounded surface facing down. This should be done before the plate has cooled entirely. Gently smoke the ground with a burning bundle of tapers (about 10 bound spirally from the bottom with masking tape) so that the carbon softens the wax and is absorbed into it. Start further away from the plate and as the ground starts appearing shiny brush the tip of the flame (about an inch above the visible flame) across the plate in a systematic pattern. This will take a bit of practice but the plate should cool to a uniform semi mat finish. I harden the wax at this point by running it under a cold tap. Any powdery carbon on the surface can be gently rubbed away with an orange polishing duster. Examine carefully for any specks of copper showing through as THESE WILL BE BITTEN!
The surface can now be drawn on using a variety of instruments. I have used an old dart with a pencil screwed into the barrel and presently use a sewing needle threaded through a propelling pencil instead of leads!
Hard ground is not much darker in colour than the metal. so it is quite common to darken the plate by carefully holding it upside down and allowing the carbon from burning wax tapers to be absorbed into the ground. This is called smoking the plate. The plate can now be drawn on with a needle – hard enough only to scrape off the ground without scratching into the metal. This way mistakes can be painted out with a liquid ground. Also remember anything drawn will print as a mirror image!
Etching of Watchbell street ,Rye - plate just prior to being bitten in acid, exposed copper showing through the smoked hard ground
Watchbell Street, Rye
The Copper plate before biting; a good example of the contrast of lines drawn on a smoked plate. TThe small square patch on the righthand side shows where the plate was held by a clamp for smoking.
When the plate is immersed into acid* the exposed areas are bitten and when the wax is removed the drawn image is revealed as having been “etched” into the plate. The plate can then be inked up with ink being driven into the etched lines. The plate is then wiped in order to remove the ink from the surface. A sheet of dampened paper is placed over the inked plate and both are rolled through a press under high pressure The rolling action and the pressure cause the ink to be squeezed out and sucked out on to the paper. The resulting etchings are characterised by extremely fine lines and subtle tones.
Successive biting to different depths can be precisely controlled with experience to create an infinite number of  tonal variations.
*I use Dutch mordant: which is composed as follows: Hydrochloric, 200 grammes; chlorate of potash, 20 grammes; water, 880 grammes. This acid works slowly and evenly without undercutting the lines and without losing its strength as it bites. Nitric acid is more vigorous, but can cause deep lines to merge

SOFT GROUND ETCHING
A copper plate is covered thinly with soft-ground; a non drying wax which is resistant to acid. Any textured object pressed onto the wax will pull the wax off when removed and leave an approximation of its texture. Placing paper over the plate and drawing on it will therefore create textures echoing pencil marks and some degree of “shading” can be achieved. The plate can then be immersed in acid and bitten and then printed.
STICKS AND STONES Soft ground etching-  plate just prior to being bitten in acid. exposed copper showing through the light soft ground resist
The etchings above use a combination of hard and soft ground. The image is initially drawn out using a pencil and paper over the plate to give a soft tonal pencil sketch effect. After biting the plate is covered with hard ground and the lines and tones are deepened and texture and detail added.
Sticks and Stones:
Plate before biting
Sticks and Stones:
First print off  plate
Sticks and Stones:
Final state
STICKS AND STONES Soft ground etching -  first print after biting soft ground stage
Copper plate with smoked hard ground in a bath of Dutch Mordant. Colour of acid shows it is reaching middle age! The scariest part of etching is undoubtedly the acid although endless films featuring bubbling, steaming bottles and beakers brandished by babbling mad scientists has given acid a worse image.
Rembrandt  van Rijn
(1606 - 1669)
Self portrait Etching by Rembrandt Van Rijn, probably one of the greatest etchers
RECOMMENDED PRINTMAKING SUPPLIERS

LAWRENCE ART SUPPLIES
T N Lawrence & Son Ltd.
208 Portland Road, Hove, BN3 5QT, United Kingdom
Phone: 0845 644 3232 (+44 1273 260260)
9 Playhouse Court,
62 Southwark Bridge Road,
London, SE1 0AT
Tel: 020 7928 2633
Janis Goodman etchings
Janis Goodman etchings
ETCHING LINKS
“The Printmaker is a most peculiar being… delights in deferred gratification and in doing what does not come naturally. He [she] takes pleasure in working backward or in opposites: the gesture that produces a line of force moving to the right prints to the left, and vice versa; a deeply engraved trench in a copper or zinc plate prints as a depression in the paper. Left is right. Right is left. Backward is forward. The Printmaker… must see at least two sides to every question.”

Jules Heller
FURTHER READING
With etching having been around for such a ling time  it is not surprising that a good many books have been written on the subject - the best by practicising printmakers.

The Art of Etching by E S Lumsden is the book I used when first learning etching and I still have that original battered and acid stained copy! This is the best technical guide to etching I have found and contains sate by state examples of the author’s own etching as well as a good selection of the best known Etchers
Also worth  buying:
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Ryepress resources is an Amazon “Astore” in which I have gathered together a selection some of the Art Materials and equipment that I have used personally and can therefore recommend.