DO try this at home! 2nd Bite: ACID!

The scariest part of etching is undoubtedly the acid! Endless films featuring bubbling, steaming bottles and beakers brandished by babbling mad scientists has given acid a bad image. YES! it is dangerous and should definitely be handled with care, especially at the mixing stage. NEVER add water to acid to dilute it - it will heat rapidly, probably spit and possibly explode. ALWAYS dilute acid by adding it slowly to cold water and ALWAYS in a well ventilated room with running water at hand in case of spills.

Nitric acid, which when diluted 1 part acid to 7 parts water gives a perfectly adequate bath for either copper or zinc ( do not use for both as the fumes can be dangerous) is a fast working solution, ideal for beginners, classes and experimental work. It bites vigorously and aggressively and can quickly lose its potency. It also tends to undercut and move sideways making close fine lines and hatching difficult to bite deeply. It tires quickly and timing can be difficult.

Dutch Mordant is an ideal mixture for Copper and can be used for zinc. It bites evenly and slowly, straight down and is very controllable. It slowly turns a bright turquoise with successive use and this can be accurately used to gauge its age and therefore strength.

Ferric Chloride is used for copper. This bizarre solution is, I believe, more of a salt than an acid (I'm actually not too hot on the chemistry of all this!). Looking suspiciously like Worcester sauce it corrodes the plate, leaving a sediment which can impede its action on fine lines unless the plate is suspended upside down in the solution. It will stain anything it comes in contact with a rusty yellow and a few unnoticed spills can reduce anything metal to a crumbly biscuit texture in a frighteningly short time (I have lost a metal bath this way!)

Biting Times

This is the area where the experience bit kicks in. How long should you leave a plate in the acid? The only real way of finding out whether a plate has been properly bitten is actually to clean it off and print it! I have seen many students ruin days of elaborate drawing by removing the plates too early and discovering their etching is a mere spidery faint ghost of what they wanted, or too late and finding that the subtly rendered tones they were hoping for have merged into one muddy, turgid black mess. Overbiting a plate will not just simply make it darker; in some cases fine, close hatching will merge and the resulting open area will have no texture to hold the ink - resulting in pale dusty looking "bald" areas with hard black edges.

How quickly, and deeply the acid bites is a matrix of several different variables:

Age of the acid - Fresh acid will have a relatively aggressive initial phase. Older acid will have a more sustained but slower bite

Room temperature - Acid reacts quicker the warmer it is and in doing so will heat up even more. Allow anything up to 25% longer for cold acid.

Area of metal exposed - An evenly distributed and elaborate drawing will bite quicker and more evenly than a drawing with heavily worked areas and large unexposed areas; the acid will also be "attracted" to the heavily worked areas in preference to individual lines or details.

How long the plate has been worked on - No-one works in a sterile environment and so the older exposed lines will have been in contact with the air for longer. They will have oxidised or have attracted grease from the air or hand. This will mean recently drawn areas will bite quicker and deeper. A solution of vinegar and salt carefully dabbed over the plate with a cotton wool ball will freshen the older lines somewhat.

A formula for achieving an set number of evenly spaced tones:
I used to have a spreadsheet which I am currently trying to resurrect which worked out the exact timings for an adjustable number of tones. I will make it available eventually! (I am presently trying to convert a spreadsheet on my old Psion3a to Excel.... aaargh!!)

In the meantime here is the timing I generally use. In principal it adopts the same mathematical progression as camera shutter speeds or f stops.

1a Initial sketch with simple tones ; SOFT GROUND, Dutch Mordant on Copper - 30 minutes and remove ground

2aSecondary drawing with shadows and more detailed mid tones : SOFT GROUND, Dutch Mordant on Copper - 1 hour and remove ground

Apply coating of hard ground, smoke and do not remove between bites.
HARD GROUND, Dutch Mordant on Copper working from darkest black downwards:

1b First Bite Black - 2 Hr (Total 4 Hr)
2b Then: Darker shadows - 1 hr (Total 2 Hr)
3b Shadows - 30 min (Total 1 Hr)
4b Mid - 15 min (Total 30 min)
5b Light - 8 min (Total 15 min)
6b Light 4 min (Total 8 min)
7b Lightest 4 min (Total 4 min)
8b White

Giving a total of 8 tones including White with a total of 4 Hours biting time
Each tone is double/half the time of the next
Hatching can be "interlaced" to create intermediate tones

Whilst the initial bite and lightest bites may seem extremely separated, remember that as you complete each succesive tone, more and more of the plate is exposed, effectively accelerating the action of the acid.

I always think of acid as working like a group of hungry kids being let loose on an empty sweet shop; swarming around the brightest and stickiest sweets available and devouring them ravernously until too full to move!

DO try this at home!

Plate with Hard Ground (smoked) and finished print

Watchbell Street, Rye

Etching by Colin Bailey

When I first joined an etching class at Working Mens College in Camden way back when it seemed pretty obvious that was not something you'd do at home; draws full of bizarre medieval devices, bottles of evil smelling liquid and walls covered with yellowing uncompleted prints. All this dominated by a huge press that felt as if it had been there long before anyone had thought of putting a building around it.

The class was in the basement down a long dark corridor and entering it felt at times like being the member of a secret sect of alchemists. I was one of the few people to take my plate home with me; carefully wrapped up in tissue. I would turn up the next week, having done all the drawing and spend most of the class stopping out the scuffs and marks that invariably had sneaked in during its transportation. Eventually I managed to smuggle home a small bottle of acid and before long was using the valuable 2 hours a week of the class solely for the precious business of printing.

I ended up teaching the class and have always tried to find modern alternatives that retain the spirit of traditional methods but can be done in the average home. Here are the technoques I now employ, with a few ideas you might not see anywhere else.

Firstly, If you havent't already got it I would highly reccomend you get a copy of:

THE ART OF ETCHING

E.S LUMSDEN

Dover Publications

ISBN-13: 978-0486200491

This was my bible in the beginning - some of the Does and Don't can be stretched a tad!

Preparing the plate
I use 16 gauge copper plate (1/16th inch) from Intaglio printmaker which comes in 500mm x 1000mm 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 lay each plate face (covered side) down on several sheets of newspaper in a well ventilated room or not too windy garden. This none polished surface is then given an even and thorough covering of an acetone based car spray paint. (I used to get mine from a firm in Kings Cross that sold it to Taxi drivers - be careful not to get a none acetone paint as it will come off in the acid. ) That done, I roughly bevel the edges of the plate to a 45° angle using a coarse file. This is optional but I then 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 edge to the prints.

After removing the plastic coating I clean the adhesive residue off with white spirit and check for scratches. If the 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 washing powder works as a substitute (be careful of the particularly gritty ones!). 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.

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!)

Hard Ground
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 advise smoking the plate.

Smoking the plate
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!

I will be adding more about different grounds, acid times and printing tips later!
Colin Bailey
Ryepress