The New Etching Chemistry SEARCH THE SITE
Friedhard Kiekeben
A variety of marks printed from a brass plate, using the Edinburgh Etch process.
Using as a resist: Sharpie, Crisco, wax crayon, dry brushed acrylic, acrylic wash etc.
Friedhard Kiekeben
A variety of marks printed from a brass plate, using the Edinburgh Etch process.
Using as a resist: Sharpie, Crisco, wax crayon, dry brushed acrylic, acrylic wash etc.
Etching Without Acid: Metal Salt Etching
Developments in etching chemistry have made it possible for metal plates to be etched in metal salt solutions rather than acid. The new and safer method, Metal Salt Etching, can and has effectively replaced the traditional acid etching approach in many shops, studios and schools.
Since the first publication of the Edinburgh Etch process in 1997, I have been able to further develop, test, and refine a comprehensive range of new metal salt etching processes for all metals used in intaglio printmaking and for sculptural plate making. The system comprises specific metal salt solutions for the fast and accurate erosion of copper, brass, zinc, steel and aluminum. All of these etching processes are compatible with common resists, including the whole range of mark making methods, such as HARD GROUND, stop out or AQUATINT within ACRYLIC RESIST ETCHING.
The benefits of this new etching methodology over the traditional acid etch approach are compelling, both in terms of safety and in regard to the quality of the bitten work. In 2003, the safety benefits of Metal Salt Etching were scientifically validated by the RIT chemists Dr Paul Craig and Dr Paul Rosenberg (CLICK FOR ARTICLE) in the context of my contribution to Keith Howard's book The Contemporary Printmaker. Key researchers such as Keith Howard, Nik Semenoff, Eva Figueras, and Cedric Green, also endorse the use of metal salts for etching.
This web site will be updated regularly to give visitors the latest developments and information on Metal Salt Etching.
The Science of Metal Salt Etching
Metal Salt Etching comprises two basic kinds of process:
The Edinburgh Etch (© F.K. 1997), suitable for copper, brass, and steel consists of a specific solution of ferric chloride with the addition of citric acid as a chelating agent or catalyst.
The Saline Sulfate Etch (© F.K. 2002) is designed for etching zinc, aluminum, and mild steel and consists of a copper sulfate and sodium chloride mixture in equal parts. Due to their low hazard rating, the metal salt etching methods are both suitable for use in a professional printmaking environment as well as in an artist's personal studio.
Both these salts have been used for centuries but their potential for etching is not fully harnessed when used without a catalyst. In fact, I would argue that this knowledge remained unexplored because metal salts were judged as if they were acids. But metal salts do not corrode metal through the destructive and harmful processes that typify acid etching; by contrast they owe their etching properties to electrical attraction in which atoms of the metal plate are elegantly removed by other metal compounds that are dissolved in a salt solution.
Today we know that this is an electrical kind of chemistry, more akin to the workings of a battery than the corrosive action of strong acids. Think of the rabbit in the Duracell adverts: a battery on a full charge will give plenty of electrical energy so the rabbit runs at full tilt, whilst a weak or depleted battery will soon stop the toy rabbit from moving at all. The difference lies in the strength of the electrical charge: the rabbit with the biggest charge wins. The salt based etching bath with the right kind of addition of a catalyst equally works as if on a full charge.
Cause and Effect: Nitric Acid Toxicity
Toxic nitric oxide fumes are produced in traditional etching with nitric.
Plate feathering exacerbates health risks.
In contact with chlorine based cleaning products, highly toxic mustard gas may be emitted.
Traditional acid etching processes produce significant amounts of toxic fumes. In the commonly used nitric acid etch, for example, the nitrous oxide gases produced are suspected of causing eye, nerve, lung, and kidney damage, as well as impotence and genetic effects.
I experienced one of these hazards at first hand. During the making of the large-scale etched installation Project David (pictured below) in 1988, whilst still using nitric acid, I contracted a severe infection in both eyes (conjunctivitis). Thanks to a good doctor and antibiotics I made a full recovery, but the incident made me determined to find alternatives to strong acids for etching.
In contact with the chlorine found in common cleaning products, nitric acid can even turn into mustard gas! This extreme hazard is not just theoretical: there is anecdotal evidence of several mustard gas incidents that occurred at professional print studios, both in the UK and the USA.
In industry today, strict regulations prohibit the use of nitric acid without fully extracted and filtrated glove units similar to those used in the nuclear industry. Regrettably, despite these compelling facts, many artists, workshops, and printmaking departments still maintain that their existing measures provide adequate protection. It is hoped that this resource will contribute to the dissemination of current thinking about safe practice for artists, specifically in the field of printmaking but also in a wider art-making context (see HEALTH + SAFETY).
Safe and Simple
The Metal Salt Etching System is free from harmful gas emissions. During etching, the chemical reaction by-products are contained within the etching solution without polluting the workshop atmosphere. The processes are not heat generating, and no vicious reactions can occur during the etching of a plate.
So inert are these processes that extraction and containment can be seen as an additional, not an essential, safety measure. Over the past two decades there have been reports of just two cases of an allergic reaction to the smell of ferric chloride. In these extremely rare instances, alternative etching methods such as the Saline Sulfate Etch or photopolymer printmaking can be used by the sensitized person.
Metal Salt Etching is so much safer because, like a battery, it is based on the principle of electrolysis: metal ions are elegantly exchanged between the poles of two kinds of metal that have an energy potential between them; the old acid etching approach has a much more aggressive chemistry.
No new printmaking process, however safe or simple, would be worth its salt if the results did not equal or exceed those produced by traditional means. Perhaps, the most exciting fact about the Edinburgh Etch and the Saline Sulfate Etch is that the results are startlingly good, biting plates quickly and cleanly. The metal salt solutions remain constant throughout their usable life, without the gradual deterioration that causes the unwanted foul-biting and undercutting that is a common feature with the use of conventional acid solutions.
Friedhard Kiekeben, Project David, seven steel etchings and plates, 1988
Developments in etching chemistry have made it possible for metal plates to be etched in metal salt solutions rather than acid. The new and safer method, Metal Salt Etching, can and has effectively replaced the traditional acid etching approach in many shops, studios and schools.
Since the first publication of the Edinburgh Etch process in 1997, I have been able to further develop, test, and refine a comprehensive range of new metal salt etching processes for all metals used in intaglio printmaking and for sculptural plate making. The system comprises specific metal salt solutions for the fast and accurate erosion of copper, brass, zinc, steel and aluminum. All of these etching processes are compatible with common resists, including the whole range of mark making methods, such as HARD GROUND, stop out or AQUATINT within ACRYLIC RESIST ETCHING.
The benefits of this new etching methodology over the traditional acid etch approach are compelling, both in terms of safety and in regard to the quality of the bitten work. In 2003, the safety benefits of Metal Salt Etching were scientifically validated by the RIT chemists Dr Paul Craig and Dr Paul Rosenberg (CLICK FOR ARTICLE) in the context of my contribution to Keith Howard's book The Contemporary Printmaker. Key researchers such as Keith Howard, Nik Semenoff, Eva Figueras, and Cedric Green, also endorse the use of metal salts for etching.
This web site will be updated regularly to give visitors the latest developments and information on Metal Salt Etching.
The Science of Metal Salt Etching
Metal Salt Etching comprises two basic kinds of process:
The Edinburgh Etch (© F.K. 1997), suitable for copper, brass, and steel consists of a specific solution of ferric chloride with the addition of citric acid as a chelating agent or catalyst.
The Saline Sulfate Etch (© F.K. 2002) is designed for etching zinc, aluminum, and mild steel and consists of a copper sulfate and sodium chloride mixture in equal parts. Due to their low hazard rating, the metal salt etching methods are both suitable for use in a professional printmaking environment as well as in an artist's personal studio.
Both these salts have been used for centuries but their potential for etching is not fully harnessed when used without a catalyst. In fact, I would argue that this knowledge remained unexplored because metal salts were judged as if they were acids. But metal salts do not corrode metal through the destructive and harmful processes that typify acid etching; by contrast they owe their etching properties to electrical attraction in which atoms of the metal plate are elegantly removed by other metal compounds that are dissolved in a salt solution.
Today we know that this is an electrical kind of chemistry, more akin to the workings of a battery than the corrosive action of strong acids. Think of the rabbit in the Duracell adverts: a battery on a full charge will give plenty of electrical energy so the rabbit runs at full tilt, whilst a weak or depleted battery will soon stop the toy rabbit from moving at all. The difference lies in the strength of the electrical charge: the rabbit with the biggest charge wins. The salt based etching bath with the right kind of addition of a catalyst equally works as if on a full charge.
Cause and Effect: Nitric Acid Toxicity
Toxic nitric oxide fumes are produced in traditional etching with nitric.
Plate feathering exacerbates health risks.
In contact with chlorine based cleaning products, highly toxic mustard gas may be emitted.
Traditional acid etching processes produce significant amounts of toxic fumes. In the commonly used nitric acid etch, for example, the nitrous oxide gases produced are suspected of causing eye, nerve, lung, and kidney damage, as well as impotence and genetic effects.
I experienced one of these hazards at first hand. During the making of the large-scale etched installation Project David (pictured below) in 1988, whilst still using nitric acid, I contracted a severe infection in both eyes (conjunctivitis). Thanks to a good doctor and antibiotics I made a full recovery, but the incident made me determined to find alternatives to strong acids for etching.
In contact with the chlorine found in common cleaning products, nitric acid can even turn into mustard gas! This extreme hazard is not just theoretical: there is anecdotal evidence of several mustard gas incidents that occurred at professional print studios, both in the UK and the USA.
In industry today, strict regulations prohibit the use of nitric acid without fully extracted and filtrated glove units similar to those used in the nuclear industry. Regrettably, despite these compelling facts, many artists, workshops, and printmaking departments still maintain that their existing measures provide adequate protection. It is hoped that this resource will contribute to the dissemination of current thinking about safe practice for artists, specifically in the field of printmaking but also in a wider art-making context (see HEALTH + SAFETY).
Safe and Simple
The Metal Salt Etching System is free from harmful gas emissions. During etching, the chemical reaction by-products are contained within the etching solution without polluting the workshop atmosphere. The processes are not heat generating, and no vicious reactions can occur during the etching of a plate.
So inert are these processes that extraction and containment can be seen as an additional, not an essential, safety measure. Over the past two decades there have been reports of just two cases of an allergic reaction to the smell of ferric chloride. In these extremely rare instances, alternative etching methods such as the Saline Sulfate Etch or photopolymer printmaking can be used by the sensitized person.
Metal Salt Etching is so much safer because, like a battery, it is based on the principle of electrolysis: metal ions are elegantly exchanged between the poles of two kinds of metal that have an energy potential between them; the old acid etching approach has a much more aggressive chemistry.
No new printmaking process, however safe or simple, would be worth its salt if the results did not equal or exceed those produced by traditional means. Perhaps, the most exciting fact about the Edinburgh Etch and the Saline Sulfate Etch is that the results are startlingly good, biting plates quickly and cleanly. The metal salt solutions remain constant throughout their usable life, without the gradual deterioration that causes the unwanted foul-biting and undercutting that is a common feature with the use of conventional acid solutions.
Friedhard Kiekeben, Project David, seven steel etchings and plates, 1988
