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Safer procedures in printmaking

Ad Stijnman
printmaker, printhistorian
Oudewater, the Netherlands

This is an excerpt of my articles: Cleaning printing plates and brushes with VCA, and Etching zinc plates with copper sulphate. In this excerpt alternative materials and techniques for printmaking are described shortly. For more technical details, see both articles. The emphasis is on the possible dangers of etching with mineral acids and cleaning with volatile organic solvents.

There are three ways toxic materials can enter the body: by inhalation, ingestion or through the skin. Preventing inhalation is the most difficult to do. Using exhausts or masks will overcome this problem only partly. Some gas, vapour or aerosol will still be left in the air you and the people around you inhale, while masks are unpractical in workshop situations. What you do not inhale will pollute the environment. Instead of using all kinds of equipment it is better to fight the problem at the source. That means using non-volatile cleansers and mordants, as this will prevent the biggest health- and environmental problems.

Vegetable Cleaning Agents (VCA) are a group of so-called alkyl-esters, which are chemical compounds of a kind of alcohol and a kind of vegetable oil, such as soy oil or coconut oil. VCAs are not volatile and are suited as cleansers for printing plates, brushes, metal, glass and plastic objects in general. They can do the same as Ligroin and White Gasoline - and more. Their big advantage is that they are not volatile and therefore cannot harm your body. Also, no exhaust system is needed in the studio. Since early 2002 one type of VCA is for sale in Japan, the so-called EkoWash.

VCAs remove oil based printing ink, wax, oil, vaseline, wax-containing etching grounds, and asphaltum. VCAs are not suited for cleaning screens in screenprinting.

Cleaning the printing plate goes in three steps:
1 - Cover the etching plate or relief block with a little VCA and let stand for at least one minute to dissolve the ground or ink. The VCA cannot evaporate and if needed you can leave it on the plate for a day or longer.
2 - Remove the mixture of VCA and ink or ground from your plate with a rag, and brush the plate with some soap and water.
3 - Rinse the plate with water and dry it immediately. After some practice you will find you need only a quarter of the amount of VCA compared to cleaning with Ligroin.

Cleaning lithographic stones is almost the same as cleaning with White Gasoline.
1 - Dampen the gummed stone with a wet sponge.
2 - Pour a little VCA on the stone and gently rub the image drawn on the stone with a rag, adding some drops of VCA if needed. The fatty image will show darker than by cleaning with White Gasoline.
3 - Squeeze a wet sponge above the stone, this prevents VCA getting into the sponge. Rub the stone with a rag. The VCA will not penetrate the stone, but will float on the water, with the crayon or tusche dissolved in it. Remove water + VCA with another rag.
4 - Pour some gum on the stone and rub it all over with a sponge.
5 - The stone can be dampened and inked in the normal way now. You will need only two or three proofs before starting to print. Soiling of the blank parts of the stone will not happen.

Brushes for oil paint, alkyd paint, or liquid etching ground are cleaned the same way as with Ligroin. Afterwards wash them with water and soap. Do not dilute your paint, etching ground or ink with VCA. Because the VCA does not evaporate it will dissolve them. Metal, glass, plastic and stone tools can be cleaned with VCA and afterwards washed with water and soap. Prevent VCA dripping in your printing press. Woodblocks can be cleaned with VCA, but care has to be taken, because it penetrates into the block and cannot be removed.

Copper Sulphate
 Copper sulphate (CuSO4) is a blue salt which can be used for etching zinc plates without toxic vapours coming from the bath. The process is simple. Copper sulphate is mixed with plain water until dissolved. The standard mixture is 100 gram of salt with 1 litre of water. This is suited for normal line etching. Use stronger mixtures for relief etching and weaker for soft-ground and aquatint. Place your prepared zinc plate in the bath and etch it. A black sediment will appear. Carefully brush it from the plate with a feather. The sedirising from the plate. This is hydrogen gas. The amount of gas is too small to be harmful. No exhaust system is needed, normal ventilation of the studio will do.

Organic Psycho Syndrome caused by Volatile Solvents
Cleaning printing plates, paint brushes and other equipment is still often done with Volatile Organic Solvents (VOS). The VOS used often by Japanese Printmakers are Ligroin and White Gasoline. VOS dissolves printing ink, litho crayon and etching ground, but only as long as it is fluid. It evaporates quickly where-after new solvent has to be used. Evaporation does not mean the solvent is gone. On the contrary, its vapour is in the air around you and you inhale it with every breath you take. When in your lungs, the vapour is readily taken up in the blood stream and transported to the brains in twenty seconds. Your brain and the rest of your nervous system consists mainly of fat. VOS will dissolve this fat and thereby cause disturbances in your functioning, like electrical wire which has been stripped of its insulation.

The disfunctioning of your brain shows largely through a combination of psychic or mental problems. The condition is called "Organic Psycho Syndrome" (OPS). Inhaling VOS for the first time may create feelings of irritation, aggressiveness, restlessness, euphoria (as in sniffing glue to get a high), irritation of the respiratory system, coughing, smarting eyes, confusion and headache.

The most important indications of a lighter form of OPS are: dizziness, sleeping problems (either too much or not enough), fatigue, feelings of depression or melancholy, loss of interest in daily activities, loss of concentration, slowness in activities, and feelings of drunkenness. On the weekend and during holidays these complaints usually diminish or may even disappear.

With long-term or chronic exposure disfunctioning of the brain increases and is continuous. Common complaints are: forgetfulness, motorial disturbances such as convulsions and forms of paralysis, insomnia, aggressiveness, changing mood, depression and melancholy. Ultimately there is permanent brain damage, which causes definitive change of personality, permanent loss of memory, paralysis and dementia. See the OPS-website in the Bibliography of the article on VCA.

Some kinds of volatile solvents affect certain organs specifically, such as the liver or the kidneys, or may cause anaemia, infertility or leukemia.

Toxic Vapours during Etching
 Metal printing plates are usually etched with nitric acid, hydrochloric acid, Dutch Mordant or ferric chloride. These etching fluids produce toxic fumes and toxic aerosols, which corrode the skin, eyes, teeth and their metal fillings, mucous membranes, lungs, and may cause impotency. The metal equipment in a studio is corroded by the vapours, too.

Metal dust comes into your nose and mouth while working in your studio, it happens by inhaling the dust or by eating, drinking or smoking in the studio. This dust and the metal fillings in your teeth are corroded by the vapours rising from the acid bath. The chemical compounds, which are formed in this process, are toxic. After swallowing these they settle in your intestines in minute amounts. In the beginning there is too little of it present to notice any negative effects. In the long run, however, the functioning of your intestines is disturbed with a range of possible ill effects.

Health and Safety Precautions
The following basic guidelines apply to both VCA and copper sulphate. For more details see both articles.
- Wear rubber gloves in preparing the solution of copper sulphate and during etching.
- Wear rubber gloves during cleaning with VCA.
- VCA and copper sulphate are not volatile, but are still aggressive to the skin. Therefor, prevent skin and eye contact in general. Rinse with plenty of water after contact.
- Do not ingest VCA or copper sulphate. If ingested rinse your mouth with water and drink a lot of water. See your doctor.
- In general it is advisable for pregnant women not to work with chemicals.
- If you have spilled some etching fluid or VCA remove it with a wet rag while you are wearing rubber gloves.
- Clean your face and hands, and rinse your mouth, before drinking, eating or smoking.

For assistance and advice you can contact the author Ad Stijnman. E-mail



版画家 版画歴史家





1 ―ほんの少しのVCAによってエッチング・プレートあるいはレリーフ版等の表面を覆い、グランドかインクを溶かすために少なくとも1分間待ちます。VCAは蒸発することができません。もし落としにくい素材など、必要に応じてより永くVCAを覆ったままにすることが可能です。
2 ―ぼろ布であなたのプレートからVCAとインクの混合物あるいはグランドを取り除き、その後、洗剤および水を使って、ブラシでプレートを擦り洗います。
3 ―水でプレートをすすぎ、それを直ちに乾かす。慣れてくれば、リグロインで洗浄することと比較して、VCAの量はは4分の1だけで済む事が分るでしょう。

1 ―ぬれたスポンジで、アラビアゴムで覆われた石(アルミ版)を湿らせます。
2 ―ほんの少しのVCAを石の上にたらし、イメージの上を優しくぼろ布で擦ります。必要ならばもう少しVCAを加えます。油分の着いているイメージの部分は、ホワイトガソリンで洗浄するときよりも、その部分はより暗く見えるでしょう。
3 ―石の上をぬれたスポンジで滑らせます。これは、スポンジに入るVCAを防ぎます。ぼろ布を使って石の上を摩擦って下さい。VCAは石に浸透しないだろうが、それに溶かされたクレヨンか解墨と共に水に浮かぶでしょう。別のぼろ布で水+VCAを取り除いて下さい。
4 ―再びある程度のアラビアゴムを石の上にたらし、スポンジで全体にガムをのばします。
5 ―石は今正常な(いつも通りの)方法で湿らせてインクにつけることができます。印刷し始める前には2回か3回の試し刷りだけが必要でしょう。描かれていない部分がよごれるような事は起りません。


硫酸銅 (CuSO4)は腐食用バッド(トレイ)から発生する有毒蒸気のないもので、亜鉛プレートの腐食のために使用することができる、青い塩です。そのプロセスは単純です。溶かされるまで、硫酸銅は普通の水と混じり合っています。標準の混合は水の1リットルに対して100グラムの硫酸銅です。これは普通のラインエッチングに適しています。レリーフエッチングのためには、より強い混合を使用する。そしてソフトグランドおよびアクアチントにはより弱い腐食液のバットに準備した亜鉛プレートを置いて、それを腐食してください。黒い沈殿物は現われるでしょう。注意深く鳥の羽でプレートからそれを払いのけてください。沈殿物は金属に付着しないが、エッチングを遅らせることになる。広い面が露出している部分をを腐食すると、小さな泡がプレートから上昇するのを見るでしょう。これは水素ガスです。ガスの量は小さすぎるので、有害になりえません。排気装置ほどのものは必要ありません。通常の換気で十分です。








- 硫酸銅の解決策を準備する際、及び腐食中にゴム・グローブを着用してください。
- VCAで洗浄する際には、ゴム・グローブを着用していてください。
- VCAおよび硫酸銅は揮発性ではないが、皮膚に対してまだ危険です。そのために、一般に、皮膚およびアイコンタクトを防いでください。触れた場合は多くの水ですすいでください。
- VCAあるいは硫酸銅を口にしたりしないでください。もし入ってしまった場合は、水で口をすすぎ、多くの水を飲んでください。そして医者に診てもらってください。
- 一般に言える事ですが、妊娠している女性にとって、化学薬品を使用したりそれを扱う仕事をしないことが望ましい。
- もし腐食液やVCAをこぼした場合は、ゴム・グローブを着用してぬれたぼろ切れでそれを削除します。
-  あなたの顔および手を清潔にしてから、飲酒したり、食事をすること、あるいは喫煙の前にも、あなたの口をすすいでください。