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Lithography
Lithography is a method of printing from a stone or a metal plate with a smooth surface and was initially used mostly for musical scores and maps. Intaglio is the family of printing and printmaking techniques in which the image is incised into a surface and the incised line or sunken area holds the ink.
General Chemicals
The main chemicals used in lithography and relief printing are inks, pigments, and acids.
Use the following information to learn more about lithography.
- Inks
- Pigments
- Solvents
- Acids
- Plate and Stone Preparation
- Printing and Cleanup
- Intaglio
- Etching
- Other Techniques
- Printing and Cleanup
Inks
Intaglio, lithography and relief inks are made of a vehicle (either linseed oil or water) that suspends pigments. Additional hazardous binders, preservatives, etc. may also be included.
Hazards
- Oil-based inks contain treated linseed oils. Ingestion of treated linseed oil in large amounts may be hazardous due to the small amounts of heavy metals present.
- Rags soaked in oil vehicles may spontaneously combust if heated.
Precautions
- Know the materials you plan to work with. Always review the SDSs for all chemicals used in a process so that you are fully aware of the hazards and how to mitigate those hazards, and use the least toxic and least hazardous materials possible.
- Avoid using lead pigments and concentrated acids whenever possible.
- Do not use an open flame or open heating element to heat linseed oil, varnishes, or burnt plate oil. Take normal fire prevention measures.
- Place oil-soaked rags in self-closing disposal cans or a pail of water and remove from the studio each day.
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Pigments
Pigments are the colorants used in lithography, intaglio, and relief printing inks. There are organic and inorganic pigments. Those with heavy metal components can cause various health issues. Please see the Painting Page [INSERT LINK] for more details on pigment hazards.
Hazards
- Lead pigments can cause anemia, gastrointestinal problems, peripheral nerve damage (and brain damage in children), kidney damage and reproductive system damage.
- Chromate pigments (chrome yellow and zinc yellow) may cause skin ulceration and allergic skin reactions.
- Some inorganic pigments, in particular cadmium pigments, chrome yellow and zinc yellow (zinc chromate) may cause lung cancer if inhaled. Please see the Painting Page [INSERT LINK] for more details on pigment hazards.
- Lamp black and carbon black may contain impurities that can cause skin cancer. Other hazards of organic pigments are not known.
Precautions
- Avoid mixing dry pigments whenever possible. If you plan to mix dry pigments, use appropriate engineering controls such as a chemical fume hood or slot hood. If you do not have access to local exhaust ventilation, please contact the EHS Respiratory Program (@email) for assistance and evaluation of your process.
- Avoid contact with pigments whenever possible. Consider wearing gloves to minimize the possibility of exposure. If skin contact does occur, wash the area immediately. Baby oil can be used to remove materials from your skin that are not readily water soluble.
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Solvents
Organic solvents are used in printmaking to dissolve and mix with oils, resins, varnishes, and inks. They also clean plates, rollers, tools, and even hands.
Hazards
- Inhalation is the main route of solvent exposure. High concentrations of solvent vapors can cause dizziness, nausea, fatigue, loss of coordination, or coma. These effects may also increase the chances for mistakes and accidents.
- Repeated or prolonged skin contact with solvents can cause defatting of the skin and resultant dermatitis. Skin absorption can also be harmful.
- Many solvents are toxic if ingested (for instance, swallowing 1 ounce of turpentine can be fatal).
- Most solvents are either flammable or combustible.
Precautions
- Have adequate ventilation in place when using solvents. If ventilation is inadequate, contact EHS (@email) for an evaluation of your process and assistance with selection and fit-testing of appropriate respiratory protection.
- Only keep the minimum amount of solvents necessary, and purchase in the smallest practical container size. Large amounts of solvents should be stored in a flammable storage cabinet.
- Never store solvents or solvent-containing materials in food or drink containers. Always label the contents of a container with the full name written out.
- Wear gloves when handling solvents to avoid skin contact. Select gloves that are appropriate for the solvent that you are using. Some solvents can readily permeate certain types of gloves. Consult the EHS guide on Glove Selection [INSERT LINK] for additional information. Use baby oil rather than solvents to clean ink off your extremities.
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Acids
Acid etching is used in intaglio and lithography. Nitric acid, hydrochloric acid, and phosphoric acid are examples of common etching acids used in printmaking. If you use hydrofluoric acid, review the Institutional SOP on HF [INSERT LINK]for handling and emergency procedures before commencing work.
Hazards
- Chemical etching requires very strong, concentrated acids. These are very corrosive to the skin, eyes, respiratory system and gastrointestinal system. Even diluted acids can still cause skin irritation on repeated or prolonged contact.
- Chromic acid is a dermal sensitizer, suspect carcinogen, and oxidizer.
- Phenol is highly toxic by skin absorption and ingestion. Exposure may cause severe kidney damage, central nervous system effects and even death if exposed to large quantities. Exposure to phenol can also cause deep and painful skin burns.
- Concentrated nitric acid is a strong oxidizing agent and can react explosively with other concentrated acids, solvents, and the like. Nitric acid emits various nitrogen oxide gases, including nitrogen dioxide, which is a strong lung irritant and can cause emphysema, pulmonary edema, bronchitis, methemoglobinemia, pneumonitis, and more.
Precautions
- Know the materials you plan to work with. Always review the SDSs for all chemicals used in a process so that you are fully aware of the hazards and how to mitigate those hazards, and use the least toxic and least hazardous materials possible.
- Read a procedure-specific or institutional Standard Operating Procedure (SOP) before beginning work with concentrated acids. Consult the corrosives section (pg. 30) of the UMass Chemical Hygiene Plan [INSERT LINK] for more information.
- Store concentrated nitric and chromic acids away from organic materials to prevent fires.
- Always add the acid to the water when diluting concentrated acids, never the reverse.
- Wear appropriate thick gloves, chemical splash goggles, and a protective apron over a lab coat when handling acids.
- Make sure there is adequate ventilation when doing acid etching, such as an enclosed fume hood. If Local Exhaust Ventilation [INSERT LINK] is unavailable, you may need to use a respirator; please contact EHS (@email) for evaluation of your process and assistance with selection and fit-testing of appropriate respiratory protection.
- Use of corrosive materials should only occur in locations where there is immediate access (i.e., within 50 ft.) to eyewashes and drench showers.
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Plate and Stone Preparation
Hazards
- Strong acids like phosphoric, nitric, acetic, hydrochloric, Hydrofluoric Page [INSERT LINK] and tannic acids are used. Please see the discussion on Acids above and consult the corrosives section (pg. 30) of the UMass Chemical Hygiene Plan [INSERT LINK] for more information.
- Lithotine, kerosene, and mineral spirits irritate the eyes, lungs, and skin, and may cause intoxication if inhaled.
- The solvents in vinyl lacquers may include highly toxic isophorone and cyclohexanone. Methyl ethyl ketone (MEK), which is moderately toxic, is often used as a thinner.
- Dichromate salts -- often found in etch, counteretch, and fountain solutions -- may cause skin and nasal ulceration and allergic reactions, and are suspected cancer-causing agents.
- Rosin dust buildup may explode (especially in enclosed rosin boxes, and near an ignition source), and may cause asthma or allergic dermatitis if inhaled.
- Talcs may be contaminated with asbestos and silica.
- Airbrush drawing materials and spray enamel paints are hazardous to inhale.
- Lifting litho stones improperly poses an ergonomic hazard.
Precautions
- Know the materials you plan to work with. Always review the SDSs for all chemicals used in a process so that you are fully aware of the hazards and how to mitigate those hazards.
- Use the least toxic solvents possible. Lithotine and mineral spirits are less toxic than the more irritating kerosene (see solvents section for more details).
- Use asbestos-free talcs such as baby powders.
- Avoid dichromate-containing solutions, and strong acids like hydrofluoric acid or phenol, whenever possible.
- Don appropriate gloves, chemical splash goggles and a protective apron over a lab coat or smock when mixing or using concentrated acids (see acids section for more details).
- Use of corrosive materials should only occur in locations where there is immediate access (i.e., within 50 ft.) to eyewashes and drench showers.
- When lifting litho stones, use appropriate techniques, mechanical aids, or another person’s help.
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Printing and Cleanup
Solvents are used to remove lithographic images, make image corrections, and clean the press bed and rollers.
Hazards
- The solvents in most roller cleaners and glaze cleaners have solvents that may cause serious health effects if ingested or inhaled.
- Most chlorinated solvents (e.g. perchloroethylene) have been shown to cause liver cancer in animals and are therefore suspected human carcinogens.
- Perchloroethylene can cause liver damage, and methylene chloride heart attacks.
Precautions
- Know the materials you plan to work with. Always review the SDSs for all chemicals used in a process so that you are fully aware of the hazards and how to mitigate those hazards, and use the least toxic and least hazardous materials possible.
- Choose products that do not contain chlorinated solvents whenever possible.
- See the discussion on solvents in the section above for more information.
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Intaglio
Intaglio is a printmaking process that involves pressing ink into depressed areas of a plate and then transferring the image to paper. Acid etching, mezzotint, drypoint, or engraving can produce the depressed regions.
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Etching
Etching involves use of a dilute acid (such as nitric acid, Dutch mordant, or ferric chloride) to cut into the zinc or copper metal plate. Some areas of the plate are protected with a waxy ground to resist the acid. Resists may include stopout varnishes with ethyl alcohol, grounds containing asphaltum or gilsonite and mineral spirits, rubber cement, rosin or spray paints.
Hazards
- Some solvents in the grounds are toxic. Inhalation of 1,1,1- Trichloroethane, for instance, is moderately toxic under normal conditions, but exposure to high concentrations may cause death.
- Concentrated nitric acid is a strong oxidizing agent and can react with many other chemicals and explode, especially organic compounds such as solvents.
- During the etching process, flammable hydrogen gas can also be produced.
- Highly toxic chlorine gas results from mixing hydrochloric acid with potassium chlorate to make Dutch mordant.
- Potassium chlorate is a potent oxidizing agent. It can react explosively with organic compounds, sulfur compounds, clothing, and even dirt. When heated, it can violently decompose into oxygen and potassium chloride.
- Rosin dust (and asphaltum dust, which is used less often) is combustible. Static electricity is enough to initiate an explosion in enclosed rosin and aquatint boxes. Rosin dust may also cause asthma and dermatitis.
Precautions
- Know the materials you plan to work with. Always review the SDSs for all chemicals used in a process so that you are fully aware of the hazards and how to mitigate those hazards, and use the least toxic and least hazardous materials possible.
- Use Dutch mordant with extreme caution. Ferric chloride (colloquially known as iron perchloride) is a safer substitute for etching copper plates. A ferric chloride solution might still cause minor skin irritation from prolonged contact.
- Don appropriate gloves, chemical splash goggles and a protective apron over a lab coat or smock when mixing or using concentrated acids (see acids section for more details) and solvents (see solvents section for more details).
- Use of corrosive materials should only occur in locations where there is immediate access (i.e., within 50 ft.) to eyewashes and drench showers.
- Use Local Exhaust Ventilation [INSERT LINK] when acid etching.
- Rubber cement produces toxic vapors and should only be used either in well ventilated areas or while using a respirator with organic vapor cartridges. If you think you may need respirator protection, please contact EHS (@email) for an assessment and assistance with selection and fit-testing of appropriate respiratory protection.
- Don't use hair dryers to stir up rosin dust. Hair dryers can serve as a source of ignition. Rosin (or asphaltum) boxes and storage should be explosion proof.
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Other Techniques
Drypoint, mezzotint, and engraving use sharp tools to incise lines in metal plates.
Hazards
- Beware of cuts or punctures from sharp tools.
- Long-term use of these tools can result in carpal tunnel syndrome. Severe cases can be incapacitating.
Precautions
- Maintain the sharp edges of tools by storing them with the blade protected.
- Always cut away from yourself. Use cut/puncture resistant gloves when using sharp tools. Please consult the cut and puncture prevention SOP [INSERT LINK] and the Cut Safety Video [INSERT LINK] for more information. You can also visit the glove selection guide: [INSERT LINK]
- When possible, secure plates with clamps to avoid slippage.
- Choose tools with wide handles, avoid tight grips, and take regular breaks to stretch your hand. This will minimize the chance of carpal tunnel syndrome. Set your work table height so contorted wrist positions and flexing motions are minimal.
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Printing and Cleanup
Printing involves placing the ink on the inking slab, inking the plate by hand, and then printing. Cleanup of the inking slab, press bed, and plate is done with a variety of solvents including mineral spirits, alcohol, lithotine, turpentine, etc.
Hazards
- Please refer to the discussion on pigments on the Painting Page [INSERT LINK] for information about dry pigment hazards.
- Larger amounts of solvents are necessary to clean the plate than for inking slabs or press beds, making it more hazardous.
- Turpentine, lithotine, or oil-soaked rags can spontaneously combust if improperly stored.
Precautions
- Please refer to the discussions on pigments and solvents or specific precautions.
- If Local Exhaust Ventilation [INSERT LINK] is unavailable and you think you may need respirator protection, please contact EHS (@email) for an evaluation of your process and assistance with selection and fit-testing of appropriate respiratory protection.
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