Lithography, Intaglio
and Relief Printing



By Angela Babin, M.S., Michael McCann, Ph.D., C.I.H.,
and Devora Neumark



INTRODUCTION

     This article/data sheet will introduce both hazards and safety
precautions recommended for printmaking.  There are many different
printmaking processes, including lithography, relief printing,
intaglio, and screenprinting.  These specific methods, except
screenprinting, will be addressed after a general introduction.
Readers are encouraged to obtain CSA's other relevant publications
such Water-based Inks: A Screenprinting Manual for Studio and
Classroom, (Johnson, Stinett, 1990) and the "Silk Screen Printing"
data sheet.  Disposal of waste materials and solutions is discussed
in Waste Management and Disposal for Artists and Schools, (Babin,
McCann 1992)



INKS

     Intaglio, lithography and relief inks consist of pigments
suspended in either linseed oil or water as a vehicle.  There can
be additional hazardous binders or preservatives, etc.



Hazards

1. Oil-based inks contain treated linseed oils.  While linseed oil
is not considered a hazard by skin contact or inhalation,
ingestion of large amounts of some treated linseed oils might be
hazardous due to presence of small amounts of toxic heavy metals.
Oil vehicles are flammable when heated, and rags soaked in these
may ignite by spontaneous combustion.



Precautions

1. Know what materials are used.  Obtain the material safety data
sheets (MSDSs) on all products used.  

2. Use the least toxic inks possible.  

3. Children under the age of 12 should only use water-based inks
containing non-toxic pigments, since oil-based inks require
solvents for cleanup.

4. Do not use an open flame to heat linseed oil, linseed oil
varnishes, or burnt plate oil.  Take normal fire prevention
measures (e.g. no smoking or open flames in work area). Place oil-
soaked rags in self-closing disposal cans and remove from the
studio each day.  An alternative is to place the oil-soaked rags in
a pail of water.



Pigments

     Pigments are the colorants used in lithography, intaglio, and
relief printing inks.  There are two types of pigments: inorganic
pigments, and organic pigments.



Hazards

1. Pigment poisoning can occur if pigments are inhaled or ingested.
For normal printing with prepared inks, the main hazard is
accidental ingestion of pigments due to eating, drinking or smoking
while working, or inadvertent hand to mouth contact.

2. The classic example of a toxic inorganic pigment in printmaking
is lead chromate (chrome yellow).  Lead pigments can cause anemia,
gastrointestinal problems, peripheral nerve damage (and brain
damage in children), kidney damage and reproductive system damage.
Other inorganic pigments may be hazardous also, including pigments
based on cobalt, cadmium, and manganese.  (See CSA's data sheet Art
Painting for more information)

3. Some of the inorganic pigments, in particular cadmium pigments,
chrome yellow and zinc yellow (zinc chromate) may cause lung cancer
if inhaled.  In addition, lamp black and carbon black may contain
impurities that can cause skin cancer.

4. Chromate pigments (chrome yellow and zinc yellow) may cause skin
ulceration and allergic skin reactions.

5. The long-term hazards of the modern synthetic organic pigments
have not been well studied.



Precautions

1. Obtain MSDSs on all pigments.  This is especially important
because the name that appears on label of the color may or may not
truly represent the pigments present.

2. Use the safest pigments possible.  Avoid lead pigments.

3. Children under the age of 12 shouldn't use toxic pigments.

4. Avoid mixing dry pigments whenever possible.  Never mix your own
chrome yellow, zinc yellow, chrome green, molybdate orange or any
other pigments which are known human carcinogens.  If possible, do
not mix highly toxic pigments such as lead white or cadmium colors.


5. If dry pigments are mixed, do it inside a glove box (a box with
a glass or plexiglas top and holes in the sides for arms or inside
a laboratory-type fume hood.  Otherwise, wear a NIOSH-approved
toxic dust respirator.



SOLVENTS

     In general, organic solvents are one of the most underrated
hazards in art materials.  Organic solvents are used in printmaking
to dissolve and mix with oils, resins, varnishes, and inks; and to
clean plates, rollers, tools, and even hands.  Hazards

1. Repeated or prolonged skin contact with solvents can cause
defatting of the skin and resultant dermatitis (rashes, drying and
cracking of skin, itching, etc.).  Many solvents,  for example
turpentine, methyl alcohol, toluene, and xylene,  can also be
harmful through skin absorption.

2. Inhalation of solvent vapors is the major way in which solvents
are harmful.  High concentrations of most solvents can cause
narcosis (dizziness, nausea, fatigue, loss of coordination, coma,
etc.).  This can also increase the chances for mistakes and
accidents.  Research during the last 10 years has indicated that
chronic occupational exposure to many solvents can cause permanent
brain damage, with symptoms including loss of memory, behavioral
changes, fatigue, spasticity, decreased intelligence, slower
reflexes, poor hand-eye coordination, etc.  Most of these studies
are on mixed solvents so it is difficult to implicate particular
solvents.  There is at least one documented case of such brain
damage affecting a silk screen artist.

     Solvents can also attack other organ systems besides the
nervous system.  In particular, turpentine can damage the kidneys,
toluene and chlorinated hydrocarbons can affect the liver, and
methylene chloride can affect the heart.

3. Many solvents are toxic if ingested.  This is particularly a
problem with young children swallowing solvents that have been
placed in glasses or other food or drink containers, although this
has also happened with adults.  Swallowing 1/5 ounce of turpentine
can be fatal to a 5-year old child.

4. Most solvents, except chlorinated hydrocarbons, are also either
flammable or combustible.  A solvent is flammable if its vapors can
burn below 100 F when a source of ignition is present; if the
temperature has to be over 100 F before it will burn, then the
solvent is combustible.  For example, ethyl alcohol and toluene are
flammable, and kerosene and mineral spirits (Varsol or paint
thinner) are combustible.



Precautions

1. Obtain the MSDS on all solvent products used.  Use the least
toxic solvent possible.  For example, replace the more toxic methyl
alcohol (methyl hydrate) with denatured alcohol or isopropyl
alcohol.  

2. Do not use solvents with or around children under 12 years, or
if you are pregnant or nursing.

3. Use dilution ventilation (e.g. window exhaust fan) for
exhausting less than a cup of evaporated solvent per day.  Or use
local exhaust such as a laboratory hood or or slot hood.  Adequate
ventilation can also be provided if the work area is set up
immediately in front (within 1-2 feet) of a window containing an
exhaust fan at work level.  

4. Keep minimum amounts of solvents on hand and purchase in
smallest practical container size.  Large amounts of solvents or
solvent-containing materials should be stored in a flammable
storage cabinet.

5. Never store solvents or solvent-containing materials in food or
drink containers. Always label containers.

6. Do not allow smoking, open flames or other sources of ignition
near solvents.

7. Have a class B fire extinguisher in the area.  (If ordinary
combustible materials are present, you may need a Class ABC fire
extinguisher).

8. Wear gloves when handling solvents to avoid skin contact In
particular do not use solvents to clean ink off hands.  Baby oil is
a good substitute.  

9. If ventilation is not adequate, NIOSH-approved respirators with
organic vapor cartridges can be worn.

10. Do not induce vomiting if petroleum distillates are swallowed.
Give 1-2 glasses of water or milk and contact a regional Poison
Control Center.



ACIDS

     Acids are used in intaglio (acid etching) and in lithography.
Strong acids commonly used include nitric acid, hydrochloric acid,
and phosphoric acid, and less commonly carbolic acid (phenol),
chromic acid, hydrofluoric and sulfuric acids.



Hazards

1. Concentrated acids are corrosive to the skin, eyes, respiratory
system and gastrointestinal system.  Dilute acids can cause skin
irritation on repeated or prolonged contact.  2. Chromic acid is a
skin sensitizer, suspect carcinogen, and oxidizer.

3. Phenol is highly toxic by skin absorption and ingestion.  It may
cause severe kidney damage, central nervous system effects and even
death if absorbed in large amounts.

4. Hydrofluoric acid is highly toxic and can cause severe, deep
burns which require medical attention.  There is no immediate pain
warning from contact with hydrofluoric acid.

5. Concentrated nitric acid is a strong oxidizing agent and can
react explosively with other concentrated acids, solvents, etc.
Nitric acid gives off various nitrogen oxide gases, including
nitrogen dioxide which is a strong lung irritant and can cause
emphysema.



Precautions

1. Know what is used.  Obtain the MSDS for all acids.

2. Whenever possible avoid concentrated acids.  

3. Children under the age of 12 should not be using or around
acids.

4. Doing acid etching requires working in a enclosed hood, or in
front of a slot exhaust hood or window exhaust fan at work level.

 

5. Store concentrated nitric and chromic acids away from organic
materials.  Concentrated nitric acid should always be stored
separately even from other acids.  

6. An important safety rule when diluting concentrated acids is to
add the acid to the water, never the reverse.

7. Wear appropriate gloves, goggles and protective apron or lab
coat when handling acids.

8. If adequate ventilation is not available, wear a NIOSH-approved
respirator with acid gas cartridges.  Do not use air-purifying
respirators with nitric acid because the nitrogen dioxide cannot be
detected by odor, and it is therefore not possible to detect odor
breakthrough with charcoal cartridges.  9. An emergency shower and
eyewash fountain that is not hand-held should be in studios where
concentrated acids are mixed or used.  Portable eyewash bottles are
not recommended.  If acid is spilled on your skin, wash with lots
of water.  In case of eye contact, rinse the eyes with water for at
least 15-20 minutes and contact a physician.  

10. Do not induce vomiting if concentrated acids are swallowed.

Give 1-2 glasses of water or milk and contact a regional Poison
Control Center.

11. Used acid solutions should be disposed of by neutralizing with
sodium bicarbonate (baking soda) before being poured down sink with
lots of water.  



LITHOGRAPHY


     Lithography uses either zinc and aluminum metal plates or
stones for printing.  It involves use of a variety of chemicals to
make the image ink-receptive and non-image areas receptive to water
and ink-repellent.


Plate and Stone Preparation

     A variety of drawing materials with high wax and fatty acid
content are used to make the image, including tusche and
lithographic crayons.  Airbrushing liquid drawing materials or
using spray enamel or lacquer is also common.  Other materials used
in stone or plate processing include etch solution containing acids
and gum arabic, counteretch solutions containing acids and
sometimes dichromate salts, and fountain solutions containing
dichromate salts.  Phenol (carbolic acid) has been used for
removing grease from stones, and a variety of solvents including
lithotine, gasoline, kerosene, and mineral spirits, which are used
for diluting drawing materials, washing out images and correction
of images.  Talc and rosin mixtures are also used.  Metal plates
are prepared with solvent-based vinyl lacquers.


Hazards

1. Acids used include phosphoric, nitric, acetic, hydrochloric,
hydrofluoric and tannic acids.  The concentrated acids are
corrosive and even dilute acid solutions can cause skin irritation
from prolonged or repeated contact. Hydrofluoric acid and phenol
are the most dangerous to use.

2. Lithotine, kerosene, and mineral spirits are skin and eye
irritants and inhalation can cause intoxication and respiratory
irritation. Gasoline is highly toxic because it usually contains
other toxic additives including benzene (which can cause leukemia
and aplastic anemia), lead additives, etc.

3. The solvents contained in vinyl lacquers can include highly
toxic isophorone and cyclohexanone. Methyl ethyl ketone (MEK),
which is moderately toxic, is often used as a thinner.

4. Dichromate salts may cause skin and nasal ulceration and
allergic reactions, and are suspect cancer-causing agents.

5. Rosin dust may cause asthma and allergic dermatitis.  There is
the hazard of explosion from the buildup of rosin dust, in enclosed
rosin boxes, around an ignition source.  

6. Talcs may be contaminated with asbestos and silica.

7. Airbrushing drawing materials or using spray enamel paints is
more hazardous than drawing with a brush because the inhalation
hazard is higher.


Precautions

1. Obtain the MSDS for all materials used.

2. See Acids and Solvents sections for the precautions with acids
and solvents.

3. Use the least toxic solvents.  Gasoline should never be used.

Lithotine and mineral spirits are less toxic than the more
irritating kerosene.

4. Use asbestos-free talcs such as baby powders.

5. Avoid dichromate-containing counteretches and fountain solutions
if possible.

6. Do not use hydrofluoric acid if possible.

7. Air brushing or application of spray paints should only be done
in a spray booth.

8. Local exhaust ventilation such as a slot hood, or window exhaust
fan 1-2 feet away is needed for vinyl plate lacquers.

9. Dilution ventilation (e.g. window exhaust fan) can be used when
working with small amounts of solvents.

10. An emergency shower and eyewash fountain should be installed
where concentrated acids are mixed and used.

11. Appropriate gloves, goggles and a protective apron should be
worn when mixing or using concentrated acids.

12. If adequate ventilation is not available for using solvents, a
NIOSH-approved respirator with organic vapor cartridges is
recommended.

13. Do not use phenol.



PRINTING AND CLEANUP


     Many art lithographic inks contain treated linseed oil as a
vehicle, and are thus not solvent-based.  However, some
lithographers use commercial lithographic inks which can contain
some solvents, such as mineral spirits.  For all types of
lithographic inks, solvents are used to make image corrections on
the press, to remove images, and to clean the press bed and
rollers.


Hazards

1. Some roller cleaners and glaze cleaners can contain chlorinated
hydrocarbons such as perchloroethylene and methylene chloride.
Most chlorinated solvents (except 1,1,1-trichloroethane) have been
shown to cause liver cancer in animals and are therefore suspect
human carcinogens.  In addition perchloroethylene can cause liver
damage, and methylene chloride heart attacks.  



Precautions

1. Know materials used.  Obtain the MSDS for all solvents.  See
Solvents section for the precautions with solvents.

2. Choose products that do not contain chlorinated solvents
whenever possible.

3. For small scale solvent use in correcting images or cleaning the
press bed using lithotine or mineral spirits, dilution ventilation
(e.g. window exhaust fan) is sufficient.

4. For roller and glaze cleaning, and larger scale solvent use,
local exhaust ventilation such as a slot hood is recommended.
Similarly, a window exhaust fan can be set up within 1-2 feet of
the work station.

5. If local exhaust ventilation is not present, use NIOSH-approved
respirators with organic vapor cartridges for larger scale solvent
use or if using chlorinated solvents.


Intaglio

     Intaglio is a printmaking process in which ink is pressed into
depressed areas of the plate and then transferred to paper.  These
depressed areas can be produced by a variety of techniques,
including acid etching, drypoint, engraving and mezzotint.



Etching

     Etching involves use of dilute nitric acid, Dutch mordant
(hydrochloric acid plus potassium chlorate) or ferric chloride to
etch the zinc or copper (respectively) metal plate.  Unetched parts
the plate are protected with resists such as stopout varnishes
containing ethyl alcohol, grounds containing asphaltum or gilsonite
and mineral spirits, rubber cement, and rosin or spray paints for
aquatinting.  Sometimes, soft grounds contain more toxic solvents.



Hazards

1. See Solvents section for the hazards of solvents.  1,1,1-
trichloroethane found in some soft grounds is moderately toxic by
inhalation under normal conditions but may cause fatalities at very
high concentrations.

2. See Acids section for the hazards of acids.  In particular
nitric acid etching releases the respiratory irritant nitrogen
dioxide which has poor odor warning properties.  Large acute
overexposures may cause pulmonary edema (chemical pneumonia), and
chronic exposure may cause emphysema.  During the etching process,
flammable hydrogen gas is also produced.

3. Concentrated nitric acid is a strong oxidizing agent and can
react with many other chemicals, especially solvents or other
organic compounds, to cause a fire.

4. Mixing hydrochloric acid with potassium chlorate to make Dutch
mordant produces highly toxic chlorine gas.  Several years ago,
five art students and teachers had chlorine poisoning in Canada
from mixing Dutch mordant without proper ventilation.  Potassium
chlorate is a key ingredient in many pyrotechnics, and is a potent
oxidizing agent.  It can react explosively with organic compounds,
sulfur compounds, sulfuric acid or even dirt or clothing.  On
heating it can violently decompose to oxygen and potassium
chloride.  Storage and use are very dangerous require special
precautions especially when mixing.

5. Rosin dust (and asphaltum dust which is also sometimes used) is
combustible.  Sparks or static electricity have caused explosions
in enclosed rosin and aquatint boxes.  Rosin dust may also cause
asthma and dermatitis in some individuals.

6. Inhalation of solvents and pigments can result from use of
aerosol spray paints.



Precautions

1. Obtain the MSDS for all materials used.

2. See Solvents and Acids sections for specific precautions.

3. Secondary schools should not use Dutch mordant.  Artists,
colleges and universities should use it with extreme caution.  A
safer substitute for etching copper plates is ferric chloride (iron
perchloride).  This forms acidic solutions so should be handled
accordingly, but does not have the dangers of handling concentrated
acids.  Ferric chloride solution might cause minor skin irritation
from prolonged contact.

4. Application of grounds or stopouts should be done with local
exhaust ventilation, (e.g. slot or enclosed hood).  Working
immediately in front of a window containing an exhaust fan at work
level will also provide adequate ventilation.

5. Application of spray paints should be done inside a spray booth
that exhausts to the outside, or outdoors.

6. Acid etching should be done with local exhaust ventilation.  See
section on precautions for Acids for more information.  Note that
the acid gases will eventually corrode ordinary fans or galvanized
ducts.

7. Rosin (or asphaltum) boxes should be explosion-proof.  Use

sparkproof metal cranks, explosion-proof motors, or compressed air.
Don't use hair dryers to stir up rosin dust.  


OTHER TECHNIQUES


     Drypoint, mezzotint and engraving use sharp tools to incise
lines in metal plates.  



Hazards

1. One major hazard associated with these types of processes
involves accidents with sharp tools.

2. Long-term use of these tools can cause carpel tunnel syndrome,
which can cause numbness and pain in the first three fingers.
Severe cases can be incapacitating.



Precautions

1. Keep tools sharp, store them safely and always cut away from
yourself.  

2. When possible, clamp down plates to avoid slippage.

3. Minimize the chance of carpel tunnel syndrome by choosing tools
with wide handles, avoiding tight grips, and doing hand flexing
exercises during regular rest periods.  Set work table height so
wrist flexing motions are minimal.



Printing and Cleanup

     Intaglio inks contain pigments, treated linseed oil and
modifiers.  Printing involves placing the ink on the inking slab,
inking the plate by hand, and then printing.  Cleanup of inking
slab, press bed, and cleaning the plate is done with a variety of
solvents including mineral spirits, alcohol, lithotine, turpentine,
etc.



Hazards

1. Preparing your own inks from dry pigments can involve inhalation
of toxic pigments.  See Pigments section for the hazards of
pigments.

2. See Solvents section for the hazards of solvents.  Plate
cleaning is more hazardous than cleaning inking slabs or press beds
because larger amounts of solvents are used.

3. Lithotine, turpentine, or oil-soaked rags can be a spontaneous
combustion hazard if improperly stored.



Precautions

1. See Pigments and Solvents sections for the specific precautions
for pigments and solvents.

2. Dilution ventilation (e.g. window exhaust fan) is sufficient for
cleaning press beds and inking slabs if small amounts of solvents
are used.  

3. For cleaning resists off etching plates, use local exhaust
ventilation, (e.g. slot or enclosed hood).  Working immediately in
front of a window containing an exhaust fan at work level will also
suffice.

4. Oil-soaked rags should be stored in approved, oily waste cans
that are emptied each day.  An alternative is to store them in a
pail of water and then allow them to dry out for reuse or dispose
of the wet rags by placing in a plastic bag.

5. NIOSH-approved respirators with organic vapor cartridges can be
used if ventilation is not adequate.



Relief and Other Printing Processes

     Other printing processes include relief printing, collagraphs,
monoprints, and plastic prints.



Relief Printing

     Relief printing techniques include woodcuts, linoleum cuts and
acrylic plates for plaster relief.  These techniques involve the
cutting away of plate areas that are not to be printed.  Relief
inks can be oil-based or water-based.



Hazards

1. Some woods used for woodcuts can cause skin irritation and/or
allergies. This is particularly true of tropical hardwoods.  See
CSA's data sheet on woodworking for more detailed information.

2. Accidents involving sharp tools can result in cuts.

3. Wood carving and cutting tools can cause carpel tunnel syndrome.
This was discussed earlier in the section that included drypoint
and mezzotint.

4. Caustic soda (sodium hydroxide) is sometimes used for etching
linoleum.  It can cause skin burns and severe eye damage if
splashed in the eyes.  

5. Eating, drinking or smoking while printing can result in
accidental ingestion of pigments.

6. Hazardous solvents are used in stopouts and resists in linoleum
etching, and for cleaning up after printing with oil-based inks.
See Solvents section for more information on the hazards of
solvents.



Precautions

1. Obtain the MSDS for all materials used.

2. See Acids and Solvents sections for precautions with acids and
solvents.  

3. Children under the age of 12 should not be doing woodcuts
because of the tool hazards.  Linocuts using heat-softened linoleum
and water-based inks can be used with older children.

4. Water-based inks are preferable to oil-based inks since solvents
are not needed.

5. Use dilution ventilation (e.g. window exhaust fan) when applying
resists for linoleum plates.

6. Wear appropriate gloves, goggles and protective apron when
handling caustic soda.

7. An emergency shower and eyewash fountain should be available. If
the chemical is spilled on your skin, wash with lots of water.  In
case of eye contact, rinse the eyes with water for at least l5-20
minutes and contact a physician.  

8. Vacuum or mop up all wood dust so as to diminish inhalation of
wood dust.  

9. Always cut in a direction away from you, with your free hand on
the side or behind the hand with the tool.

10. Carpel tunnel syndrome can be minimized or avoided by using
tools with wide handles, avoiding tight grips, and rest periods
with hand flexing exercises.  Linoleum cutting is softer to work,
and thus can reduce musculoskeletal injury.



Collagraphs

     Collagraphs are prints produced by using a collage of
different materials glued onto a rigid support.   A wide variety of
materials and adhesives can be used in making collagraphs.



Hazards

1. Rubber cement, a common adhesive used with collagraphs, is
extremely flammable and most rubber cements and their thinners
contain the solvent n-hexane which can cause damage to the
peripheral nervous system (hands, arms, legs, feet) from chronic
inhalation.

2. Epoxy glues can cause skin and eye irritation and allergies.

3. See the Solvents section for solvent hazards found in adhesives.

4. Spraying fixatives on the back of collagraph plates to seal them
can involve risk of inhalation of the solvent-containing spray
mist.

5. Sanding collagraph plates which have been treated with acrylic
modeling compounds or similar materials can involve inhalation of
irritating dusts.

6. A wide variety of other materials with varying toxicities can be
used in making collagraph plates.



Precautions

1. Know the hazards of materials used.  Obtain the MSDSs from the
manufacturer.  

2. Use the least toxic materials available.  In particular use
water-based glues and mediums (e.g. acrylic medium) whenever
possible.  Some rubber cements are made with the solvent heptane,
which is less toxic than n-hexane, primarily because peripheral
neuropathy is not associated with its use. 

3. Use dilution ventilation (e.g. window exhaust fan) with small amounts of
solvents and large amounts of acrylic medium (due to the presence
of small amounts of ammonia).  For highly toxic solvents or large
amounts of solvents or other toxic chemicals, use local exhaust
ventilation (e.g. slot hood, enclosed hood, etc.).  A window
exhaust fan can be used if set up only 1-2 feet away.

4. Use spray fixatives in a spray booth that exhausts to the
outside, or outdoors.

5. Wear gloves when using epoxy glues.

6. Wear a NIOSH-approved toxic dust respirator when sanding
collagraph plates.



Plastic Prints

     Plastic prints can involve making prints from a wide variety
of plastic materials and resins.  



Hazards

1. Plastic prints can involve hazards from inhalation of plastic
resin vapors (e.g. epoxy resins) and also from inhalation of
decomposition fumes from drilling, machining, sawing, etc. of
finished plastics.



Precautions

1. Obtain the MSDS for all materials used.

2. See Solvent section for the precautions with solvents.

3. Use the least toxic material available.

4. Use dilution ventilation (e.g. window exhaust fan) with small
amounts of solvents and when fabricating finished plastics.  For
highly toxic solvents or plastics resins, or large amounts of
solvents or other toxic chemicals, use local exhaust ventilation
such as a slot or enclosed hood, or a window exhaust fan 1-2 feet
away.

5. Wear a NIOSH-approved respirator with organic vapor cartridges
when using plastics resins if local exhaust ventilation is not
available.  





Monoprints

     Monoprints involve standard intaglio, lithographic and other
printmaking techniques, but only one print is made.  Monoprints
have the same hazards involved in plate preparation and printing as
the parent techniques.



Photoprintmaking

     Photoprintmaking involves exposing a light-sensitive emulsion
or film to ultraviolet light through a transparent support
containing an opaque image to transfer the image to a plate.  The
transparency through which the photoemulsions are developed can
include drawings on a transparent support such as Mylar or acetate,
or photographic images processed on graphic arts film to yield a
positive image.  Several photoprintmaking methods will be
discussed.



Photolithography

     Photolithography involves transferring graphic images to
stones or metal plates that are coated with a light-sensitive
emulsion.  One can coat the stone or metal plate, or use
presensitized metal plates.  Light-sensitive emulsions used on
stone consist of a mixture of powdered albumin, ammonium
dichromate, water, and ammonia; commercial emulsions are usually
based on diazo compounds.  Developing solutions for these mixtures
often contain highly toxic solvents.  Diazo-sensitizing solutions,
developers with highly toxic solvents, plate conditioners
containing strong alkali, and other brand name mixtures are used
for metal plates.  



Hazards

1. Diazo photoemulsions are the least hazardous although they can
cause eye irritation.  

2. Ammonium dichromate used for stone is a probable human
carcinogen, is moderately toxic by skin contact, and may cause
allergies, irritation, and external ulcers; it is highly flammable
and a strong oxidizer.  

3. Ammonia is a skin irritant and highly toxic by inhalation.
Ammonia is highly corrosive to the eyes.  It has good odor-warning
properties.

4. Light exposure sources include photoflood lamps, vacuum Poly-
Lite units, and carbon arcs.  Carbon arcs produce large amounts of
ultraviolet radiation which can cause skin and eye damage and
possible skin cancer.  Carbon arcs also produce hazardous metal
fumes, and ozone and nitrogen dioxide (which can cause emphysema),
and toxic carbon monoxide.

5. Screen cleaning solutions include strong caustic solutions,
enzyme detergents which can cause asthma, and chlorine bleach.
These are skin and respiratory irritants.

6. Many solvents used in developing solutions are highly toxic both
by inhalation and skin absorption.

7. Plate conditioners contain alkalis that are highly corrosive to
skin and eyes.



Precautions

1. Obtain a MSDS for all materials used.

2. See Solvents section for more precautions with solvents.

3. Avoid ammonium dichromate and use presensitized plates if
possible.  If you cannot substitute, wear gloves and goggles.
Store it away from heat, solvents and other organic materials.

4. Use ammonia solutions or solvent-containing photolithographic
solutions inside a laboratory hood, or in front of a slot exhaust
hood.  Wear gloves, goggles, and if ventilation is inadequate, a
NIOSH-approved respirator with organic vapor cartridges for
solvents, and an ammonia cartridge for ammonia.

5. A window exhaust fan provides the minimum ventilation needed for
using bleach.

6. Do not use carbon arcs unless they are equipped with local
exhaust ventilation exhausted to the outside.  Quartz mercury or
metal halide lamps are safer.

7. Paint walls in the darkroom with a zinc oxide paint which will
absorb ultraviolet radiation.  When using the carbon arc, wear
welding goggles with as dark a shade number as enables you to see.

8. Wear gloves, goggles and plastic apron or laboratory coat when
mixing hazardous chemicals.  A glove box or wear a NIOSH-approved
toxic dust respirator when mixing powders.

9. If you spray diazo photoemulsions without a local exhaust spray
booth, wear goggles and a NIOSH approved toxic dusts and mists
respirator.

10. An eyewash fountain should be available.  In case of splashes
in the eyes rinse with water for at least 15-20 minutes and contact
a physician.



Photoetching

     Photoetching is usually done using the KPR products.

Photoresist dyes often contain a variety of highly toxic solvents,
including ethylene glycol monomethyl ether acetate (2-ethoxyethyl
acetate, cellosolve acetate), ethylene glycol monoethyl ether, and
xylene, and benzaldehyde.  The developers contain xylene and
ethylene glycol monomethyl ether acetate (2-methoxyethyl acetate or
methyl cellosolve acetate).   Developers used for safer
presensitized plates also also contain solvents.  Exposure of the
plate is done with ultraviolet sources such as carbon arcs, mercury
lamps, or metal halide lamps.



Hazards

1. See the Solvents section for the hazards of various solvents.
In particular, methyl and ethyl ether acetates of ethylene glycol
are highly toxic by skin absorption and inhalation and can cause
anemia, kidney damage, testicular atrophy and sterility in men, and
miscarriages and birth defects in pregnant women.  

2. Xylene is moderately toxic by skin absorption, and highly toxic
by inhalation and ingestion.  It is a strong narcotic.

3. The Photolithography section discusses carbon arc hazards.



Precautions

1. See Solvents section for precautions with solvents.

2. Pregnant or nursing women, children, and men trying to conceive
should not work with these materials.

3. Use photofloods or other light sources instead of carbon arcs.
Precautions with carbon arcs is discussed in the Photolithography
section.

4. Use presensitized plates if possible.

5. Use photoresist solutions with local exhaust ventilation, or
wear an organic vapor respirator.  Wear butyl rubber gloves when
handling KPR solutions.



Other Photoprintmaking Techniques

     Rarer techniques include photogravure, using rosin and
ammonium bichromate, and photoimage wood engraving.



Hazards

1. Photogravure uses an aquatint technique involving rosin dust or
asphaltum.  See Etching under Intaglio for hazards of rosin dust.

2. Potassium dichromate is used as a developing agent in
photogravure.  Potassium dichromate may cause skin and nasal
ulceration and allergic reactions, and is a suspect cancer-causing
agent.

3. Photoimage wood engraving uses photoemulsions.



Precautions

1. Use sunlight, photofloods or other light sources instead of
carbon arcs.

2. Wear gloves, goggles and protective apron when handling
potassium dichromate.

3. Wear a NIOSH-approved toxic dust respirator when mixing powders.

4. An eyewash fountain should be available.  In case of splashes in
the eyes rinse with water for at least 15-20 minutes and contact a
physician.



Film Developing

     High contrast graphic arts films such as Kodalith are used to
produce photographic images for photoprintmaking.  There are
various hazards of darkroom chemistry.  These, and recommended
safety precautions, are discussed in other CSA publications on
photographic processes.  



For Further Information

     Written and telephoned inquiries about hazards in the arts
will be answered by the Art Hazards Information Center of the
Center for Safety in the Arts.  Send a stamped, self-addressed
envelope for a list of our many publications.  Permission to
reprint this data sheet may be requested in writing from CSA.

Write: Center for Safety in the Arts, 5 Beekman Street, Suite 820,

New York, NY 10038.  Telephone (212) 227-6220.

     CSA is partially supported with public funds from the National
Endowment for the Arts, the New York State Council on the Arts, the
New York City Department of Cultural Affairs, and the NYS
Department of Labor Occupational  Safety and Health Training and
Education Program.




This article was originally printed for Art Hazard News, © copyright Center for Safety in the Arts 1992. It appears on nontoxicprint courtesy of the Health in the Arts Program, University of Illinois at Chicago, who have curated a collection of these articles from their archive which are still relevant to artists today.