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Nontoxic Printmaking, Safe Painting & Printed Art



Electro-Etching Made Easy                  CONTENT  |  SEARCH

Alfonso Crujera, Gran Canaria Island, Spain,


please note:


This authoritative text on the subject has recently been updated (2012);

many thanks also to Bob Perkin for his assistance in
correcting some translation errors related to voltage and current;
Alfonso Crujera is currently working on a new book on the subject.

(also of interest, a simplified explanation to help understand electro-etching:)

     Electro-Etching: The Basis



 

Electrolytic tank and accessories

Introduction

Since the 1980s a real change has taken place in traditional etching. Printmakers became aware that materials used in workshops and art schools were harmful to health and the environment. Research was focused in several areas: Acid mordants were replaced by sulfate and salt mordants or by etching with electricity - free of toxic fumes. Methanol based varnishes were replaced by acrylic and oil based resists. Rosin and asphaltum powders were replaced by acrylic sprays. Hydrocarbon solvents used for cleaning plates and inks were replaced by vegetable cleaning agents and cheap oil-seed products.

 

Old processes were rediscovered and new methods were incorporated using modern materials such as polymers for the practice of intaglio, digital and laser processes etc. Virtually all these techniques have proved popular with those printmakers who are more health-conscious and environmentally sensitive, and amongst those who are more curious and eager to experiment.

 

Fortunately, these alternative processes have been gradually spreading across the world of modern print arts. More and more publications, and websites such as this one, now feature extensive information about many of these alternative methods.

 

Among the rediscovered techniques is electro-etching, developed in the 19th Century by Thomas Spencer and then almost forgotten in the printmaking world. Why, I do not know. But now it has been revived through its association with safe or low-risk modern printmaking, thanks to research by Nik Semenoff, Cedric Green, Marion and Omri Behr, and the workshop of Ole Larsen (where I had the opportunity to begin my own research into the technique). These printmakers have been testing and demonstrating the usefulness and safety of electrolytic processes for etching.

 

The reinvigorated technique offers a wide range of new features, graphics and innovative possibilities but has not enjoyed the same spread or level of acceptance as other non-toxic processes - perhaps because of an unfounded fear of electricity, or the apparent "expensive paraphernalia" to set up an electro-etching unit. In truth, the electrical "know-how" is very simply, and you do not need expensive equipment.

 

I believe that electro-etching is a 21st Century technique that's here to stay! And I hope to contribute to its revival and popularity by showing how with these easy instructions.

 

 

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The Fundamentals of the Electrolytic Processes and Electro-Etching

 

                                                                                                                   The Electrolytic Process

If you place two plates of the same metal in parallel - with no contact between them - into a salt solution (water and salt) that is electrically conductive of that same metal, then connect the plates to terminals of a direct current power supply or battery, the current will flow from one plate to the other through the solution (the electrolyte).

 

The electrolyte contains positive metal ions and negative sulfate ions. When the current flows, positive and negative ions of the electrolyte are attracted to the plate of opposite polarity. Positive metal ions are adhered or "attached" to the cathode (negative pole) and the negative sulfate ions are attracted to the bare areas of the anode (positive pole) and react with the metal surface oxidizing and eroding it. The result of this process is a bite in the metal that is comparable with an acid etching; but with some very useful differences!

 

 

The plate you wish to etch is attached to the anode (+) and placed in the tank facing (in parallel with) another plate that is attached to the cathode (-), with a distance of 6 to 10 centimeters between them.

 

While positive metal ions are becoming solid metal at the cathode, an equivalent amount of metal is being extracted from the anode, thus the electrolyte keeps its original concentration.

 

The amount of sulfate in the solution does not change, and the electrolytic bath is reusable. The solution is not depleted with use. This balance and stability in the solution allows you to calculate bite-times more accurately than with acids.

 

By using the same concentration in the electrolytic solution, the same time, and same voltage, the printmaker is able to produce a consistent bite. If you have several plates of the same dimensions and etch identical areas on those plates using the same formula (i.e. consistent electrolyte concentration, time, voltage) you will produce identical results on all the plates.

 

This process does not release toxic gases such as those produced by etching zinc or copper plates with nitric or hydrochloric acid. And, by taking some minor precautions when you introduce and remove plates from tanks or during the washing process for example, you can consider it a fairly harmless technique.

 

Electrolytic processes, using electricity, have the advantage of not producing waste, such as gas bubbles which with traditional acid etching can block the bite, nor does it produce sediment that can builds up on the plate and at the bottom of a tank as with other methods.

 

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The Electro-Etching Unit: What you will need

  • Vertical tank
  • Power supply - direct current (DC)
  • Cathode grid
  • Electrolyte

 

 

Vertical Tank

Always use a plastic tank, never metal. You can begin with small plates and an improvised tank made from a plastic water container with its top cut off, until you become familiar with the technique. You can use a flat tank or tray too: Cedric Green provides information about this method on his GREEN PRINTS website.


 

Tank DIY with a plastic water container                                    Direct Current (DC) Power Supply

   


Photographs by Helios Vega


Power Supply

You will need a power source (preferably with a variable voltage output), that supplies direct current (DC) up to 3 to 5 amps at least, equipped with digital displays and power controls. This power supply will provide a constant current flow and more secure control over the process, especially for those who are beginners and have no knowledge of electrical etching. Sometimes an electrical resistor may be included in the electrical circuit to limit the amount of electrical current which flows but this is not important for the present discussion. Cedric Green shows how you can prepare your own power supply or use batteries (cheaper systems). You can use whichever power supply you want, but always use direct current (DC).



 

 

Cathode Grid

In order for the electrolytic process to take place, a metal plate must be immersed in the tank and connected to the negative pole (-) cathode, and positioned opposite (in parallel with) another plate of the same metal, which is connected to the positive pole (+) anode. The plate that is attached to the anode is the plate that will be etched.

 

To simplify the process, instead of a cathode plate, you can use a stainless steel grid that fits the dimensions of your tank. You can appropriate the type of stainless steel grill popularly used for roasting meat. I would recommend using a different grid or grill for each of the metals that you are intending to etch.

 

 

Stainless steel Cathode grid

 

 

Stainless steel Cathode grill

 

 

 

Electrolyte

The electrically conductive salt solution is the electrolyte. You must make sure that the type of electrolyte you use is that of the same metal to be etched. Previous experiments in electro-etching used a solution of sodium chloride (common salt), and for this reason they did not have much success.

 

So remember: you must use a metal salt that matches the metal to be etched:

 

  • COPPER SULFATE (Cu SO4) for COPPER plates
  • ZINC SULFATE (Zn SO4) for ZINC plates
  • FERROUS SULFATE  (Fe SO4)  for IRON and STEEL plates

 

 

These sulfates can be obtained from suppliers of industrial chemicals. I recommend using pure sulfate, free of any impurities that can cause unknown waste and undesirable consequences in disposal (see ETCH ZINC, STEEL, ALUMINUM for more information about copper sulfate use and safe disposal). If you buy sulfate in garden stores, be very careful that it has not been mixed with other products such as fungicides etc., as the resulting electrolyte may not work.

 

Because the electrolyte solutions are not exhausted with successive bites, and therefore they do not have to be continually renew, I would advise using maximum purity sulfates.

 

Copper sulfate                                                   

 


Zinc sulfate

 

 

The concentration of metal ions in the electrolytic solution will set up the current flow and, consequently, the amount of metal that will be dissolved from the plate you are etching. Low concentrations do work slower but give effective etching. Saturated concentrations are faster but require a power supply with higher amperage. Low concentrations work slower but give effective etching. Saturated concentrations are faster but require a power supply with more current output. A high concentration joined with a high voltage can stimulate the generation of oxygen at the anode, forming - if the plate is copper - a thin but solid oxide layer, which is not dangerous but can cause etching to stop as the copper oxide is not electrically conductive. If this happens you must dilute the electrolyte.

If the plate is zinc, and the electrolytic solution is fairly concentrated, and used with a high voltage, the solution will slowly begin to change. As the zinc hydroxide is very alkaline it will increase the pH of the solution and thicken it. The earliest attempts at anodic etching were geared to these facts, and it necessitated the use of acids to neutralize the effects. There were etchers who added a small amount of sulfuric acid (0.03% / liter of solution) to their copper sulfate solution to prevent disagreeable oxidations - something which works on copper plates; but it is not recommended that sulfuric acid be added to zinc sulfate solutions since the current flow will produce a large quantity of gases.

 

Current and Voltage 

The depth of the lines produced by  electro-etching is proportional to the etching time and the amount of electrical current  flowing through the electrolyte solution (depth ∝ current x time). Consequently by increasing the current the etching time can be decreased. It is important to understand that the amount of current which can flow depends on how much bare metal is available for etching. This bare metal is a result of the  lines made in the ground when the image was drawn onto the plate with a needle or open areas of metal made to generate micro-dots. (see below micro-dot)

The electrical current is directly proportional to the voltage set on the power supply: increasing the voltage increases the current. Voltage is measured in volts and current is measured in amperes (amps). The amount of current flowing is related to the amount of bare metal it is etching as described above. If the voltage is set too high then unwanted effects may arise. Until experienced is gained with a particular electro-etching system it is better to use slower rather than faster etching.

With any of the metals and concentrations shown above, I usually use a very low voltage of  0.5 volts. For the small plates shown in this articles, the corresponding current is around 0.4 amps. With this voltage and after 15 minutes of electrolysis, we will have a printable line. A plate will need to be etched up to 60 minutes to get deeper lines.

I recommend you make step tests of single and crossed lines at intervals of 15 minutes up to a total of 120 minutes so you can discover the times needed to reach the intensity of etched lines for your work.

You can also etch with a voltage of 1.0 volt. But remember it is better to keep to low voltages (currents): to use higher values may cause the varnish/resist to become detached from the plate.

WARNING:

With 10 volts, oxygen will form at the anode and hydrogen on the cathode, and these gases together are an explosive combination.

 





Copper sulfate and zinc sulfate

Copper sulfate and zinc sulfate are salts which are usually supplied in the form of crystals, or sometimes crushed into coarse grains. When handling these crystals or powders, you should avoid breathing in the dust or allowing the material to come into direct contact with the skin. Protect yourself with a dust mask and rubber gloves while they are solid salts. Once the salts are diluted in water there is no danger of breathing in the solutions. The solutions are safe because, as explained above, they do not emit harmful gases. However, you should avoid letting the electrolyte solutions touch the skin, and be careful when you are immersing or taking plates out of tanks so as not to cause splashing into the eyes. Use goggles to be extra safe. (See more about Precautions and Safety below.)

 

  • Electrolytic solutions should be made with neutral pH water, thus the chemistry of the electrolyte will be more balanced.

  • Remember, you must use a wooden stick to dilute the salts in water, never metal.

  • Before you fill the tank, prepare the electrolyte in advance, in a plastic container - you can filter it if necessary.

  • Add one part sulfate salts to the water. Stir gently. Let the mixture stand a few minutes, then add more sulfate. Stir until the crystals are completely diluted.

  • A concentration is measured as the amount of salt per liter of water.

  • The temperature of the solution is very important. The electrolytic bath should be kept at BELOW 32ş C to prevent the electrolyte penetrate between the metal and resist.

 

Electrolyte solutions that are not being used can be left in the vertical tank. Cover the tank to avoid the solution getting contaminated or evaporated in warm weather. If you are using small quantities, the solutions can be stored in plastic bottles with caps, with an information label indicating the concentration of sulfates, date, etc.

 

I have worked with several electrolytic concentrations (amount of salt per liter of water), each of them has given me slightly different nuances. I recommend you start experimenting with a low concentration in the solution. Later, if you have sufficient amperage of power supply, you can increase concentration and continue practicing and researching.

 

 

Electrolyte to etch COPPER plates:

        

        Concentration

 

Weak: 160g COPPER SULFATE to 1 liter of WATER

 

Medium: 200g  COPPER SULFATE to 1 liter of WATER

 

Strong: 250g  COPPER SULFATE to 1 liter of WATER

 

 

Electrolyte to etch ZINC plates:

 

        Concentration

 

Weak: 160g ZINC SULFATE to 1 liter of WATER

 

Medium: 300g ZINC SULFATE to 1 liter of WATER

 

Strong: 500g ZINC SULFATE to 1 liter of WATER

 

 

Electrolyte to etch STEEL plates:

 

        Concentration

 

Medium: 200g FERROUS SULFATE to 1 liter of WATER

 

Strong: 250g FERROUS SULFATE to 1 liter of WATER

 

 

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Preparing the Plate

 

Contact-Strip

You should prepare a "contact-strip" that serves to carry or conduct current to the plate that you are going to etch. Cut a strip of the same metal that you are etching; it should be 1mm thick, 1.5cm wide, and about 12cm long. Next, prepare a piece of self-stick plastic that is a little bigger than the plate size. Place the contact-strip on the back of the plate and cover both with the self-stick plastic: this serves to attach the contact-strip and  to protect the reverse of the plate from electrolytic corrosion at the same time.

 

Setting up contact-strip and back protection of the plate

 

Self-stick plastic (yellow), contact-strip (copper), plate (copper)

 



Sanding the contact-strip

 



Contact-strip and plate

 



Protecting the back of the plate and attaching the contact-strip

with self-stick plastic at the same time

 



Back protection

 

 

 

Cut off spare plastic

 

 

 

Bend the contact-strip to hang it in the tank

 

 

 

Contact strip protection

 

 

 

Contact strip protection

 

 

 

The plate is ready



 

 

 

Degreasing the plate

Before applying resists you should thoroughly degrease the plate, using a mixture of vinegar and salt. In Spain we use a material called Blanco de Espana (bismuth oxychloride), a powder that is mixed with vinegar and rubbed onto the plate with a cotton cloth. The plate is then washed with water and dried with paper or a cloth first then with hot air, until the plate is perfectly degreased. You can also degrease the plate using a teaspoon of citric acid and a teaspoon of sodium bicarbonate (NaHCO3) mixed with a little water and rubbed onto the plate with a cloth until the plate is degreased; wash with water and dry as above.

 

It should be noted that any small amount of grease left on the plate, for instance fingerprints, will prevent etching in that area of the plate.

 

 

Pouring vinegar onto the sanded plate




A little Blanco de Espana (Bismuth Oxychloride)




Mix the Blanco de Espana and vinegar and rub into the plate

with a cotton cloth

 



Wash off with water

 



Rinse thoroughly with more water

 

 

 

Varnishes or Resists

You can protect the plate with any resists or grounds you desire, taking into account that an electrolytic action will bite, strongly, anywhere that is not fairly well protected. I am currently working on an alternative resist, like a HARD AND SOFT GROUND, using oil-based intaglio ink diluted with a little oil and a few drops of cobalt dryer which is then applied to the plate with a roller. Any ground/ink must be completely dried on the plate - use a hot-plate - before the plate can be introduced into the electrolytic bath. You can dry the ground/ink before or after drawing into the plate.

 

You can also use the ACRYLIC RESIST ETCHING options recommended on this site in the INTAGLIO MANUAL of Acrylic Resist Etching by Friedhard Kiekeben and the BEGINNERS COMPENDIUM by Donna Adams, which give information about a large number of acrylic products. I have successfully used the acrylic wax Future produced by Johnson - applying two coats of varnish and drying thoroughly with hot air between each layer.

 

 

 

Applying an acrylic resist

 

 

 

Drain the remaining resist from  one side of the plate

 

 

 

Finish draining the excess resist on the other side of the plate

 

 

 

Dry the resist using hot air

 

 

 

Proof of acrylic resist on copper:

Electrolyte concentration 250g to 1 Liter of water.

Voltage 0.5V.

Bitten at two intervals of 10 minutes and two of 15 minutes.

 

 

Current and Voltage

 

The depth of the lines produced by electro-etching is proportional to the etching time and the amount of electrical current flowing through the electrolyte solution (depth oo current x time).

 

Consequently by increasing the current the etching time can be decreased. It is important to understand that the amount of current that can flow depends on how many bare metal ions available for etching. This bare metal is the result of the lines made in the ground when the image was drawn onto the plate with a needle or open areas of metal made to generate microdots. (see below: microdot).

 

The electrical current is directly proportional to the voltage set on the power supply: increasing the voltage increases the current. Voltage is measured in volts and current is measured in amperes (amps). The amount of current flowing is related to the amount of bare metal it is etching as described above. If the voltage is set too high unwanted effects may arise. Until experience is gained with a particular electro-etching system it is better to use slower rather than faster etching.

 

With any of the metals and concentrations shown above, I usually use a very low voltage of 0.5 volts. For the small plates shown in this article, the corresponding current is around 0.4 amps. With this voltage and after 15 minutes of electrolysis, we will have a printable line. A plate will need to be etched up to 60 minutes to get deeper lines.

 

I recommend you make step tests of single and crossed lines at intervals of 15 minutes up to a total of 120 minutes so you can discover the times needed to reach the intensity of etched lines for your work. You can also etch with a voltage of 1.0 volt. But remember it is better to keep to low voltages (currents): to use higher values may cause the varnish/resist to become detached from the plate.



 

WARNING:

With 10 volts, oxygen will form at the anode and hydrogen on the cathode,

and these gases together are an explosive combination.

 

 

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Let's get to work! 

 

  • Prepare the plate with the contact-strip, then degrease it very well and cover with your chosen ground or varnish.
  • Fill your tank with a suitable electrolyte solution up to about 5cm from the rim of the container.
  • Once you have finished drawing put the plate into the tank which has previously been filled with a suitable electrolyte. 
  • The plate should be fully submerged in the tank, and opposite where you have already installed the cathode grid.

         

see images (1), (2) and (3) below 

  • The plate should be placed at a distance of approximately 6cm from the cathode. Remember that the plate and cathode grid should be parallel across the whole surface and they should not be tilted.
  • Connect the wires from the power supply with the help of some crocodile clips.

The CATHODE grid is connected to the  BLACK negative pole (-).

 

The ANODE contact-strip joined to the plate should be connected to the RED positive pole (+).

see image (4) and image (5) below 

  • Next, switch on the power supply which regulates current with controlled voltage from 0 volts, until it reaches 0.5 volts. You will see how the amperage increases gradually -  this depends on the amount of bare metal on the plate.

         

see image (6) and image (7) below 

Keep the voltage at 0.5 V.

 

Etch for 15 minutes.

  • Once the desired time has elapsed, switch off the power supply, remove the plate from the tank and flush it with water. 

(See Washing Plates and Precautions and Safety)

  • Cover any area with stop-out varnish, and then return the plate to the tank and repeat the process above.

Test at interval of 15 minute bites.

 

 

(1) Tank filled with copper electrolyte, stainless steel cathode grid

hanging at the tank side and connected with a crocodile clip

 

 

 

(2) Holding the contact-strip, the plate to be etched is introduced

to the electrolyte bath

 

 

 

(3) The plate is hung near the side of the tank, opposite (in parallel

with) the cathode grid

 

 

 

(4) The plate is connected to the (+ pole) of the power supply by a

crocodile clip

 

 

 

(5) Tank, with cathode grid and anode plate connected, before

switch on

 

 

 

(6) The power supply is switched on.

Left screen indicates 0.5V

Right screen shows 0.39 Amperes (that is the current that is

flowing proportionally to the metal being bitten)

 

 

 

(7) Close up of power supply.

RED POLE (+) connects to the PLATE to be etched 

BLACK POLE (-) connects to the CATHODE GRID

Keep the voltage at 0.5V (left screen); in this case the resulting current is 0.4 amps (right screen)

Power supplies can be purchased from companies such as

MultimeterWareHouse or MED-Worldwide

 

Perform tests using different:

  • concentrations of electrolyte
  • voltage (within safe limits)
  • time
  • distance between poles

 

 

Step Test: electro-etching lines on COPPER PLATES

Cu 1 - Electrolyte concentration 160g to 1 Liter of water. Voltage 0.5V. Bitten at 15 minute intervals.

Cu 2 - Electrolyte concentration 250g to 1 Liter of water. Voltage 0.5V. Bitten at 15 minute intervals.

Cu 3 - Electrolyte concentration 160g to 1 Liter of water. Voltage 1.0V. Bitten at 15 minute intervals.

 

Step Test: electro-etching lines on ZINC PLATES

Zn 1 - Electrolyte concentration 160g to 1 Liter of water. Voltage 0.5V. Bitten at 15 minute intervals.

Zn 2 - Electrolyte concentration 250g to 1 Liter of water. Voltage 0.5V. Bitten at 15 minute intervals.

Zn 3 - Electrolyte concentration 300g to 1 Liter of water. Voltage 0.5V. Bitten at 15 minute intervals.

Zn 4 - Electrolyte concentration 300g to 1 Liter of water. Voltage 1.0V. Bitten at 15 minute intervals.

Zn 5 - Electrolyte concentration 500g to 1 Liter of water. Voltage 0.5V. Bitten at 15 minute intervals.

 

Micro-dot (Microtint or Galv-tone)

To obtain tones like aquatint, you have simply to leave bare areas of metal. Electrolysis causes a rugged surface which will hold the ink like an aquatint. The richness of these tones depends on the structure and quality of the different metals used. If you want to get deep stippled areas for intense tones, it is best to etch in intervals of 15 minutes, rinsing the plate, allowing it to dry completely before etching again (without blocking the area) until you have etched the whole time proposed. Significantly, this method will produce more intense tones than one continuous etching of 60 or 90 minutes.

 

On copper, open bite generates a micro-dot with a scale of tones ranging from pale gray to the darkest and most intense tones using solutions of low concentration and low voltage. A voltage of 1.0 V does not produce a more intense tone of micro-dot.

 

Alternatively, you can apply a layer of intaglio ink to the plate with a roller (it is best to remove some of the ink from the roller on a newsprint sheet first). When ink is applied to the plate it creates a network of tiny ink dots that will block the whole plate or smaller areas where it has been applied, like an aquatint. Obviously this method requires skill to achieve good results.

 

You can make stop-outs with wax and lithographic pencils. You can also use splashes of varnish. A micro-dot can also be generated through galvanizing - by changing the polarity of the plates. If you wish, you can use traditional (but toxic) rosin or asphaltum to aquatint plates, but these have a tendency to lift off at certain stages in the electrolytic action. The challenge is not to use these toxic methods! Since turning away from acids, powdered and melted rosins, and methanol or turpentine cleaners the etching workshop has become a new space, so why not try out the new ways to AQUATINT.

 

I have not experimented with modern methods of acrylic aquatint applied using an airbrush, since you need two layers of varnish to resist electro-etching. Perhaps using an acrylic spray aquatint and etching for about 10 minutes and then continuing to apply acrylic sprays and etching for several intervals, will produce interesting results?

 

There are so many more nuances to electro-etching than I have space to go into in this simple 'How-To' guide, and so much more experimenting to do!

 

 

 

Step Test: Electro-etching "micro-dots" by open bite on COPPER PLATES

Cu 1 - Electrolyte concentration 160g to 1 Liter of water. Voltage 0.5V. Bitten at 15 minute intervals.

Cu 2 - Electrolyte concentration 200g to 1 Liter of water. Voltage 0.5V. Bitten at 15 minute intervals.

Cu 3 - Electrolyte concentration 250g to 1 Liter of water. Voltage 1.0V. Bitten at 15 minute intervals.


Step Test: electro-etching "micro-dots" by open bite on ZINC PLATES

Zn 1 - Electrolyte concentration 160g to 1 Liter of water. Voltage 0.5V. Bitten at 15 minute intervals.

Zn 2 - Electrolyte concentration 200g to 1 Liter of water. Voltage 0.5V. Bitten at 15 minute intervals.

Zn 3 - Electrolyte concentration 300g to 1 Liter of water. Voltage 0.5V. Bitten at 15 minute intervals.

Zn 4 - Electrolyte concentration 300g to 1 Liter of water. Voltage 1.0V. Bitten at 15 minute intervals.

Zn 5 - Electrolyte concentration 500g to 1 Liter of water. Voltage 0.5V. Bitten at 15 minute intervals.




Electro-etching lines and micro-dots on copper plate

 

Applications

The great thing with electro-etching is that you can experiment with all kinds of varnishes, acrylic and oil based. You can apply all the usual techniques of intaglio. You can also use transfers and photopolymer sheets on the plates. You can experiment with the nuances of galvanography. Electrolytic processes offer the printmaker a multiple possibilities.

 

Printing

Any plate that has been etched using the electrolytic processes described above can be printed in the usual manner. See sections on printing your plate in the INTAGLIO MANUAL and BEGINNERS COMPENDIUM.

 

 

 

Washing plates and Safe Disposal

Traditionally, etched plates which have toxic residue on them have been washing in the sink, discharging waste into the water system through drains and sewers.

Electrolytic solutions do not affect the aquifier (the water system) if certain precautions are taken.


ZINC SULFATE SOLUTION

Plates that have been etching using a zinc sulfate solution may be washed directly into the sink with generous quantities of water, because it is not harmful and does not affect the sewerage systems or water table.


COPPER SULFATE SOLUTION

However, it is recommended that plates that have been etched using copper sulfate solution be wash in a tank with water and iron filings. The reason for this is that copper ions are converted quickly and easily into metallic copper which is easily disposable and rendered harmless by contact with iron filings. Use a plastic tank or flat tray into which the etched plate will fit comfortably and which is large enough to contain plenty of water. Place some degreased iron filings or a thin piece of steel wire wool (the kind used for polishing that you can buy at any hardware store) into the tank. The tank solution will gradually become yellow in color and it is at this state that you can filter the solution then dispose of it down the drain. The plate can be removed from the tank and rinsed with water in the sink.

 


Tank containing an etched plate and steel wool, ready to be filtered  


 Use Iron Filings or Steel Wool in your tank.

 

 

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Electro-Etching Precautions and Safety Checklist

It is important to take certain precautions in order to work safely with the electro etching technique and its various applications.

 

REMEMBER:

  • Avoid breathing sulfates in its crystallized or powdered form.
  • Avoid allowing sulfates to come into direct contact with the skin and eyes.
  • When handling powdered sulfates in the preparation of the electrolyte, wear a dust mask and rubber gloves until the sulfate is fully diluted in water.
  • Use waterproof gloves if your hands have to come into contact with electrolytic solutions.
  • Use goggles to protect eyes from splashes from the electrolyte.
  • If your skin or hands accidentally get in touch with the solution, wash thoroughly with water.
  • If the electrolyte gets into the eyes, use an eye wash station or wash them with plenty of water and seek medical advice if necessary.

 

  • If you are storing the electrolyte, use plastic bottles (with plastic caps) that are well labeled, and in a safe place away from children.
  • Use the appropriate electrolyte for the plate metal being used.
  • Check all electrical connections are made correctly before switching on a power supply.
  • Remember that with electricity the red terminal is the positive pole (+) and the black terminal is the negative pole (-).
  • When the plate is ready to be etched, FIRST place it into the electrolytic tank, THEN connect the terminals and switch on the power supply.
  • Watch the power supply displays to keep the voltage in the desired range.
  • Switch off the power supply before the plate is taken out.
  • Etch using  LOW VOLTAGE (0.5 V - 1.0 V)
  • REMEMBER that at 10 volts the ions form hydrogen in the cathode and oxygen at the anode, which together are an explosive combination. Avoid generating these gases by keeping to a low voltage.
  • Use a LOW voltage and a LOW concentration of solution. A high concentration in the electrolytic solution together with a high voltage - say around 6 volts - can generate the formation of oxygen at the anode which will slow the etch.

 

 

Electro-Etching Advantages

Electro-etching offers us such an exciting alternative to traditional acid etching that I make no apology for reiterating some of those advantages here:

  • The electrolytic bite produces an impeccable and delicately etched line.
  • The bite occurs perpendicular to the surface of the plate, and therefore results in very clean and bright lines.
  • The electrolytic bite does not undermine the metal (foul bite) under the layer of protective varnish, avoiding damage to the edges of any resists.
  • Cross hatched lines retain their integrity and do not tend to unite during prolonged biting.
  • Electro-etching is highly controllable and therefore consistent. Using the same conditions i.e. the same electrolyte concentration, the same distance between anode and cathode, same time and voltage, means that the depth of the etched lines will be consistent and have the same features.
  • In contrast to what happens with acid baths where it is necessary to extract the plate immediately to stop the etching process, in  an electrolytic bath, etching stops when we flick the current switch off on the power supply. Plates can remain immersed for short periods of time with the electrolytic unit turned off, since corrosion does not continue. (Note: Over longer periods, the electrolyte can penetrate between the plate and contact-strip causing the plate to drop to the bottom of the tank, or lift the resist.)
  • At the bottom of etched lines the electrolytic action generates a rough surface in the metal which holds the ink extremely well, even with wider lines.
  • An electro-etching produces a uniform porous structure on a bare metal surface (a surface without a resist) that holds the ink. I have called this effect the "micro-dot". It is similar to traditional aquatint, but to obtain a micro-dot effect you do not need to use any of the traditional toxic materials of aquatint sprays and powders, rosin or asphaltum.

 

  • Electrolytic solutions do not generate fumes or toxic gases during the etch or when they are kept in the tanks while you are not etching.
  • Etching with electricity does not generate toxic gases.
  • By using electro-etching a workshop can save on the costly investment in a fume extractor hood to protect etchers from harmful gas emissions generated in the traditional etching with acids.
  • The electrolytic bite does not produce gas bubbles that can cause the etch to stop. Therefore it is not necessary to watch out for or remove these bubbles as is the case with acid etching. While electricity is etching you can be working at other plates.
  • The electrolytic bite does not generate metal wastes that can accumulate in incisions and obstruct the etching process.
  • Electrolytic solutions do not become exhausted with successive bites, so it is easier to calculate the time of bite.
  • Because the electrolyte does not become exhausted, this makes it a very economical method in contrast to etching with acid, where the acid solution becomes weaker with every use until it is depleted.

Electrolysis eliminates the problem of depletion completely - I'm still using the same electrolytic solutions that I started working with in 2001!

 

Electro-Etching: Some Disadvantages

Electro-etching offers a great alternative to etching with acid, but as with everything, it also has some disadvantages: 

  • You still need to take precautions with the raw sulfates and resulting electrolytic solutions.
  • A feature of electro-etching is that it will bite isolated lines deeper than those that are close together, or cross hatched lines. Also it tends to bite harder in the external areas than at the center of plates (edge-effect). In addition, electrolytic etching bites harder on the edges of wide lines and edges of resists of large areas of open bite. This is more noticeable in prolonged bites. However, all these drawbacks can be compensated for by using a cathode grid in the electro-etching unit instead of a cathode plate.
  • Using electricity to etch may put off some etchers, because  this source of energy may seem dangerous to them. As long as precautions are taken to keep the voltage and amperage used very low, there is no risk of electric shock if you should accidentally touch the electrical connectors at the same time. It is sensible, however, to avoid causing a short circuits by bad connections or by accident.
  • Some printmakers may consider not using powdered rosin or asphaltum as a limit to achieving a flat and uniform tone of different intensities - of the sort provided by the traditional aquatint.

 

 

It is a great time for looking forward in printmaking. With practice I'm sure we will find ways to avoid or remedy any minor issues. It is necessary to give some time to electro-etching, to work with the techniques to research its nuances, to make a virtue out of necessity. I hope this introduction will fire your enthusiasm to give electro-etching a try!







_________________________________
Alfonso Crujera

Website: www.crujera.com
_________________________________

 

 

 

The photographs illustrating this article were produced by Helios Vega.

Blog: http://heliosvega.blogspot.com/

 

 

 

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NOTES:

Electro-etching = Electroetch = Galv-etch = Anodic etching = Polytypi = Electrolytic etching

Micro-dot = Microtint = Microtinting = Galv-tone

 

Websites and Publications:

Nik Semenoff: http://homepage.usask.ca/~nis715/electro.html

Marion and Omri Behr. http://www.electroetch.com

Cedric Green: http://www.greenart.info/green

Alfonso Crujera: http://acrujera.blogspot.com

 

POLYTYPI by Peter Sjoblom. Sweden. 1991

GREEN PRINTS by Cedric Green. Published by Ecotech Design. France. 1998- 2004

MANUAL DEL GRABADO ELECTROLITICO by Alfonso Crujera. Spain. 2008.

 

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 Grabado Electrolitico, Alfonso Crujera (Original Spanish Text)

 Galvanografia, Alfonso Crujera


Electro Etching - The Basis, Alfonso Crujera and Bob Perkin


 

 


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_________________________________
Alfonso Crujera

Website: www.crujera.com
_________________________________

If you would like to find out more about electro-etching Crujera's excellent, fully illustrated publication Electro-etching handbook is available in English. The English version of this book was published in 2013.
 
 
Alfonso Crujera is the co-founder of a number of art groups and initiatives. A highly versatile artist that has taken part in many solo and group exhibitions, he works in a range of media including painting, engraving, sculpture, video, performance and also as a curator.
He learnt to etch with the master Felix Juan Bordes in 1976.
From 1998 to 2009 he has taught intaglio printmaking at Luján Pérez Art School in Grand Canary Island, Spain.
 
His first contact with electro-etching was in 2001 at the Ateljé Larsen in Helsingborg, Sweden. Since that time he has worked with and extensively researched all aspects of the electro-etching processes. He has written a number of articles about electro-etching and galvanography for specialised magazines: Grabado y Edición (Spain), Xilyon (Argentina), and published a handbook about this technique in Spanish: Manual del Grabado Electrolítico in 2008, in English in 2013.
 
He lectures and delivers workshops at conferences, art schools and universities. Under his direction, several electrolytic etching units have been installed in workshops in Spain and Mexico, where he has given courses on etching with electricity. He collaborates regularly with other Spanish printmakers - including Eva Figueras, Kako Castro, and Paco Mora - who have an interested in non-toxic etching.He lectures and delivers workshops at conferences, art schools and universities. Under his direction, several electrolytic etching units have been installed in workshops in Spain and Mexico, where he has given courses on etching with electricity. He collaborates regularly with other Spanish printmakers - including Eva Figueras, Kako Castro, and Paco Mora - who have an interested in non-toxic etching.
 
 
The artist now offers a residency program in his non-toxic workshop, the residence is located on the north coast of the island of GranCanaria, Spain.  In this natural environment, perfect for reflection and creativity, the artist has transformed the workshop into a workspace that is free from toxic emissions and respectful to the environment. He now proposes to share it with other artists who, inaddition to 24-hour use of the studio, will have access to the artist's direct and personal assistance. They will be introduced to the method or have the opportunity to develop their current knowledge of non- toxic etching using electricity, and to apply these techniques to carry out their own project.
 
Residency
 
Residencia
 
Member of Res Artis and Trans Artists
 

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