Poptassium Ferricyanide Crystals.
A stable molecule under room temperature conditions, this compound is known to be able to release toxic hydrogen cyanide gases when exposed to heat, UV radiation, or in the presence of strong acids.
The US safety agencies EPA, NIOSH, and the CDC have documented numerous cases of serious toxic exposure cases involving a Cyanotype chemistry used by artists and in textile art.
1). a case from 1979, in excerpts:
"The artist reported mucous membrane irritation; burning and itching sensations on her arms, face and hands; facial and finger edema, difficulty focusing eyes, sore mouth and anus, headache and nausea, which were temporally associated with the cyanotype printing process itself or contact with fabrics which had undergone the cyanotype process. The artist had not performed the process since the summer of 1979. However, she continued to report symptoms when utilizing fabrics which had been previously treated. She was also concerned about potential contamination of her work area and residence."
"The artist reported that she had first begun the cyanotype process in June 1978. She noticed a tingling in her hands and skin during the measurement of chemicals, and acute flareups of symptoms each time she engaged in the process. She discontinued use of the process in the summer of 1979. The symptoms, however, would recur from time to time. By careful observation the artist was able to link her symptoms to contact with materials which were directly or indirectly involved in the cyanotype process. The symptoms abated when she was away from home, providing she did not bring any of the treated cloth with her. The symptoms were most severe during hand stitching of the fabric into a quilt, during which time there was extensive skin contact with the cloth and some oral contact due to threading of needles, knotting of threads, etc. Occasional accidental needle pricks to the fingers also."
2.) a case from 1992 (abstract)
The health hazards involved in making handmade quilts involving a cyanotype printing process were evaluated. An artist engaged in creation of handmade quilts in her residence had experienced facial and finger edema, mucous membrane irritation, headaches, and nausea, was investigated.
The cyanotype process was used to transfer photographic prints to fabric, which was later incorporated in quilts. Chemicals used in the cyanotype process included potassium-dichromate (7778509), which is known to be highly toxic and a skin sensitizer. Even though the artist had discontinued use of the process, symptoms recurred when she handled or sewed cloth treated with the cyanotype process.
Work surfaces tested positive for contamination with hexavalent chromium (CrVI). Air and vacuum sampling indicated that CrVI was not present at detectable levels. The author recommended discontinuing the use of the cyanotype process, or discontinue use of potassium-dichromate as fixative, decontaminating the basement with soap and water, washing fabrics thoroughly in hot water, and avoiding contact with other sources of chromates.
Recent Findings show that Potassium Ferricyanide (Cyanotype Powder), is highly toxic to fish, a fact that is rarely mentioned in the 'how-to' literature on this process.
(excerpt - Researchgate)
Toxicity of Ferro- and Ferricyanide Solutions to Fish, and Determination of the Cause of Mortality
"The investigation of the causes of a fish kill in waters containing ferro- and ferricyanide at concentrations far under those generally accepted as non-lethal have shown these low concentrations to be lethal due to photo-decomposition and release of the cyanide ion. Experimental data place the toxic level of these compounds, under similar conditions of light intensity, at a concentration between 1 and 2 p.p.m. This level is assumed to vary slightly under natural conditions with latitude, period of the year, temperature, water turbulence, and interferences. Rapid development of toxicity has been demonstrated at a concentration of 2 p.p.m. of either potassium ferro- or ferricyanide."
Safety Aspects of Photography
in the Digital Age
Traditional Darkroom Processing / 'Alternative' Photography
Photography now looks back
at nearly 200 years of development.
The lens-based medium has
taken the world by storm and
fundamentally changed the way
we picture things.
The deep blue prints made in Cyanotype are very alluring, but on reflection, the chemical hazards that are present (both in the process and in the prints) may outweigh the aesthetic benefits.
EPA Environmental H&S Guide for Art Departments and Schools,Pratt (waste management guide) http://publicsafety.tufts.edu/ehs/files/P1003I69.pdf
'The most important information you can have about these processes is in this area, it could stop you becoming sensitized to the chemicals, getting sick or even save your life.Theodore Hogan makes a very relevant comment about experimenting with the limits of the materials in 'The New Photography', that illustrates the point well,: 'Just remember that you may exhaust your limits long before the materials reveal theirs'. 'Ignorance of how to safely handle the chemicals used in various printing techniques can put you out of the picture'. The chemical might still be on the shelf when you are in the grave!So a correct understanding of these materials, processes and environments to handle them in is essential.Almost all photographic chemicals can irritate the eyes, nose, throat and skin. Exposure to some chemicals such as cyanides and solvents (Turps and mineral spirits) may cause headaches, weakness, dizziness, and a sense of confusion. Prolonged exposure with chromate's may result in skin ulcers. Other chemicals can produce severe skin and lung burns, and if they get in your eyes, blindness (hydrochloric acid, oxalic acid, potash, silver nitrate).'
Alfred Stieglitz in 1902. Photo: Gertrude Käsebier (Wikipedia)
page continues below, scroll down for more in-depth content
A Safer Approach to
The most common concern related to B+W photography are respiratory in nature, shallow breathing and asthma can be caused from the mists given off by the chemicals. Ensure good air flow in the darkroom through the use of fans / extraction systems / open windows and take fresh air breaks during processing.
Also avoid leaving solutions uncovered. Part of the magic of B+W processing lies in watching the image emerge in the development tray, whilst rocking the tray or agitating the print with tongs. Actually, the image will appear just as well if left in the bath all by itself - it might just take a minute longer.
To protect your health and your lungs best cover all baths with transparent sheets of plexiglass or make hinged lids for each tray. There is a precedent for this approach: in commercial print processing development machines are used that are also fully enclosed, and that emit very little harmful vapors.
This method will substantially reduce the exposure to airborne fumes that may otherwise impede your breathing or even damage your lungs. Working with an enclosed chemistry will significantly reduce your exposure to airborne fumes that might otherwise impede your breathing, and in the long run damage your lung capacity. In the following sections we include extensive writings on the topic of photo processing safety from the book 'Making Art Safely' by Merle Spandorfer, (NY 1992), and by Michael McCann, PhD, and the Center for Safety in the Arts.
Be cautious in how you handle ammonium or potassium dichromate: It is dangerous and poisonous. This chemical can cause lesions on your tender flesh through contact and can damage your lungs by breathing it in.
In the platinotype printing process, photographers make fine-art black-and-white prints using platinum or palladium salts. Often used with platinum, palladium provides an alternative to silver.
Many artists achieve results similar to 'Alternative Photography' using a variety of printing methods and photo-transfer processes. These include silkscreen printing, 'liquid light' paint-on photo emulsions, heat transfers for inkjet or laser prints, or
Mary Stieglitz-Witte: Floral Weave, 1989
photo-transfer via color laser copier.
It involves coating a canvas with ferric ammonium citrate, tartaric acid, and silver nitrate, then exposing it to ultraviolet light. The canvas can be washed with water, and hypo to keep the solutions in place. The image created has a Van Dyke brown color when its completed, and unlike other printing methods, does not require a darkroom.
The Van Dyke brown process was patented in Germany in 1895 by Arndt and Troost. It was originally called many different names, such as sepia print or brown print. It has even been called kallitype, however that process uses ferric oxalate instead of ferric ammonium citrate.
Silver Nitrate Safety
As an oxidant, silver nitrate should be properly stored away from organic compounds. Despite its common usage in extremely low concentrations to prevent gonorrhea and control nose bleeds, silver nitrate is still very much toxic and corrosive. Brief exposure will not produce any immediate side effects other than the purple, brown or black stains on the skin, but upon constant exposure to high concentrations, side effects will be noticeable, which include burns. Long-term exposure may cause eye damage. Silver nitrate is known to be a skin and eye irritant. Silver nitrate has not been thoroughly investigated for potential carcinogenic effect.
Silver nitrate is currently unregulated in water sources by the United States Environmental Protection Agency. However, if more than 1 gram of silver is accumulated in the body, a condition called argyria may develop. Argyria is a permanent cosmetic condition in which the skin and internal organs turn a blue-gray color.
Since their introduction in 1879, palladium and platinum prints have been recognized for their permanence, tonal richness, delicacy, noble presence, and, unfortunately, for their potential adverse health effects.
These metals, when inhaled as powders or absorbed through the skin as liquids, have been associated with long-term health effects.
Some palladium salts are suspected carcinogens; platinum salts may cause a severe form of asthma known as platinosis.
Palladium and platinum procedures are similar. For palladium printing, the sensitizing solution is ferric oxalate plus sodium chloropalladite or palladium chloride.
For platinum prints (platinotype), potassium chloroplatinite or platinum chloride are used.
'Oasis', Cyanotype art on stretched cotton shown at a recent art fair in New York
Photography, which has capturedFilm-based Photography, however, is not a risk-free activity; inappropriate exposure to photochemical confers significant health risks.
the imagination of amateurs
and professionals for more than 150 years,
can be irresistible.
The seduction lies in the
myriad possibilities inspired
by aiming a lens at a subject, the simplicity of
pressing the shutter release,
and the thrill of watching
the image develop in the darkroom.
As both creators and viewers, our appetite for
representation can be insatiable.
Merle Spandorfer: 'Blue Mist Echo', 1978, gum bichromate on canvas.
'I was not given suffcient information that I was working with a lung carcinogen',
I'm fully recovered, and my art has taken new directions, and working with
nontoxic materials has become a top priority.
THREE ESPECIALLY HAZARDOUS
THEIR SOURCES DESERVE
photographic processing. Film developing is usually done in
closed canisters. Print processing uses tray processing, with
successive developing baths, stop baths, fixing baths, and rinse
steps. Other treatments include use of hardeners, intensifiers,
reducers, toners, and hypo eliminators. Photochemicals can be
purchased both as ready-to-use brand name products, or they can
be purchased as individual chemicals which you can mix yourself.
diluting, or powder form, which need dissolving and diluting.
glacial acetic acid, used in making the stop bath, is also
corrosive by skin contact, inhalation and ingestion.
moderately toxic by skin contact, due to the alkali and
developers themselves (see Developing Baths below). The
developers may cause methemoglobinemia, an acute anemia resulting
from converting the iron of hemoglobin into a form that cannot
transport oxygen. Fatalities and severe poisonings have resulted
from ingestion of concentrated developer solutions.
developing powders. Pregnant women, in particular, should not be
exposed to powdered developer.
box with glass or plexiglas top, and two
holes in the sides for hands and arms), local exhaust
ventilation, or wear a NIOSH-approved toxic dust respirator. In
any case, there should be dilution ventilation (e.g. window
exhaust fan) if no local exhaust ventilation is provided.
concentrated photochemicals. Always add any acid to water, never
available where the photochemicals are mixed due to the corrosive
alkali in developers, and because of the glacial acetic acid. In
case of skin contact, rinse with lots of water. In case of eye
contact, rinse for at least 15-20 minutes and call a physician.
shelves so as to reduce the chance of face or eye damage in case
of breakage and splashing.
accidently. Make sure that children do not have access to the
developing baths and other photographic chemicals.
para-aminophenol sulfate, and phenidone. Several other
developers are used for special purposes. Other common
components of developing baths include an accelerator, often
sodium carbonate or borax, sodium sulfite as a preservative, and
potassium bromide as a restrainer or antifogging agent.
strong sensitizers. Monomethyl-p-aminophenol sulfate creates
many skin problems, and allergies to it are frequent (although
this is thought to be due to the presence of para-phenylene
diamine as a contaminant). Hydroquinone can cause depigmentation
and eye injury after five or more years of repeated exposure, and
is a mutagen. Some developers also can be absorbed
through the skin to cause severe poisoning (e.g., catechol,
pyrogallic acid). Phenidone is only sightly toxic by
with ingestion of less than one tablespoon of compounds such as
monomethyl-p-aminophenol sulfate, hydroquinone, or pyrocatechol
being possibly fatal for adults. This might pose a particular
hazard for home photographers with small children. Symptoms
include ringing in the ears (tinnitus), nausea, dizziness,
muscular twitching, increased respiration, headache, cyanosis
(turning blue from lack of oxygen) due to methemoglobinemia,
delirium, and coma. With some developers, convulsions also can
toxic by skin contact, inhalation, and ingestion. They cause
very severe skin allergies and can be absorbed through the skin.
accelerators are highly corrosive by skin contact or ingestion.
This is a particular problem with the pure alkali or with
concentrated stock solutions.
ingestion and slightly toxic by skin contact. Symptoms of
systemic poisoning include somnolence, depression, lack of
coordination, mental confusion, hallucinations, and skin rashes.
It can cause bromide poisoning in fetuses in cases of high
exposure of the pregnant woman.
causing gastric upset, colic, diarrhea, circulatory problems, and
central nervous system depression. It is not appreciably toxic
by skin contact. If heated or allowed to stand for a long time
in water or acid, it decomposes to produce sulfur dioxide, which
is highly irritating by inhalation.
instead. If developer solution splashes on your skin or eyes
immediately rinse with lots of water. For eye splashes, continue
rinsing for 15-20 minutes and call a physician. Eyewash
fountains are important for photography darkrooms.
acid is commonly available as pure glacial acetic acid or 28%
acetic acid. Some stop baths contain potassium chrome alum as a
Fixing baths contain sodium thiosulfate ("hypo") as the fixing
agent, and sodium sulfite and sodium bisulfite as a preservative.
Fixing baths also may also contain alum (potassium aluminum
sulfate) as a hardener and boric acid as a buffer.
inhalation, skin contact, and ingestion. It can cause dermatitis
and ulcers, and can strongly irritate the mucous membranes. The
final stop bath is only slightly hazardous by skin contact.
Continual inhalation of acetic acid vapors, even from the stop
bath, may cause chronic bronchitis.
sulfate) is moderately toxic by skin contact and inhalation,
causing dermatitis and allergies.
by skin contact. By ingestion it has a purging effect on the
bowels. Upon heating or long standing in solution, it can
decompose to form highly toxic sulfur dioxide, which can cause
chronic lung problems. Many asthmatics are particularly
sensitive to sulfur dioxide.
fixing bath contains boric acid, or if acetic acid is
transferred to the fixing bath on the surface of the print.
may cause skin allergies or irritation.
slightly toxic by skin contact (unless the skin is abraded or
burned, in which case it can be highly toxic).
acetic acid vapors and sulfur dioxide gas produced in
photography. Kodak recommends at least 10 air changes per hour,
or 170 cfm for darkrooms and automatic processors. I recommend
using the larger of the two ventilation rates. The exhaust duct
opening should preferably be located behind and just above the
stop bath and fixer trays. The exhaust should not be
recirculated. For group darkrooms, the amount of dilution
ventilation should be 170 cfm times the number of fixer trays.
Make sure that an adequate source of replacement air is
provided. This can be achieved without light leakage by use of
light traps. Ducting used with local exhaust systems should
prevent light leakage from the exhaust outlet.
release of toxic vapors and gases.
is either intensification or reduction. Common intensifiers
include hydrochloric acid and potassium dichromate, or potassium
chlorochromate. Mercuric chloride followed by ammonia or sodium
sulfite, Monckhoven's intensifier consisting of a mercuric
salt bleach followed by a silver nitrate/potassium cyanide
solution, mercuric iodide/sodium sulfite, and uranium
nitrate are older, now discarded, intensifiers.
Reduction of negatives is usually done with Farmer's reducer,
consisting of potassium ferricyanide and hypo. Reduction has
also be done historically with iodine/potassium cyanide, ammonium
persulfate, and potassium permanganate/sulfuric acid.
human carcinogens, and can cause skin allergies and ulceration.
Potassium chlorochromate can release highly toxic chlorine gas if
heated or if acid is added.
is an skin and eye irritant.
be absorbed through the skin. They are also highly toxic by
inhalation and extremely toxic by ingestion. Uranium
intensifiers are radioactive, and are especially hazardous to the
and ingestion, and moderately toxic by skin contact. Adding acid
to cyanide forms extremely toxic hydrogen cyanide gas which can
be rapidly fatal.
itself, will release hydrogen cyanide gas if heated, if hot acid
is added, or if exposed to strong ultraviolet light (e.g., carbon
arcs). Cases of cyanide poisoning have occurred through treating
Farmer's reducer with acid.
oxidizers and may cause fires or explosions in contact with
solvents and other organic materials.
intensifiers, even though they are probable human carcinogens.
Gloves and goggles should be worn when preparing and using these
intensifiers. Mix the powders in a glove box or wear a
NIOSH-approved toxic dust respirator. Do not expose potassium
chlorochromate to acid or heat.
cyanide reducers because of their high or extreme toxicity.
Farmer's reducer to acid, ultraviolet light, or heat.
another metal, for example, gold, selenium, uranium, platinum, or
iron. In some cases, the toning involves replacement of silver
metal by brown silver sulfide, for example, in the various types
of sulfide toners. A variety of other chemicals are also used in
the toning solutions.
toning, or when treated with acid.
damage. Treatment of selenium salts with acid may
release highly toxic hydrogen selenide gas. Selenium toners also
give off large amounts of sulfur dioxide gas.
allergic skin reactions and asthma, particularly
in fair-haired people.
described in previous sections. In particular, wear gloves and
goggles. Mix powders in a glove box or wear at oxic dust
respirator. See also the section on mixing photochemicals.
(e.g. slot exhaust hood, or working on a table immediately in
front of a window with an exhaust fan at work level).
are not contaminated with acids. For example, with two bath
sulfide toners, make sure you rinse the print well after
bleaching in acid solution before dipping it in the sulfide
processing, including formaldehyde as a prehardener, a variety of
oxidizing agents as hypo eliminators (e.g., hydrogen peroxide and
ammonia, potassium permanganate, bleaches, and potassium
persulfate), sodium sulfide to test for residual silver, silver
nitrate to test for residual hypo, solvents such as methyl
chloroform and freons for film and print cleaning, and
concentrated acids to clean trays.
Electrical outlets and equipment can present electrical hazards
in darkrooms due to the risk of splashing water.
or potassium dichromate, produces highly corrosive permanganic
and chromic acids.
when acid is added, or if heated.
eliminators may cause fires when in contact with easily
oxidizable materials, such as many solvents and other combustible
materials. Most are also skin and eye irritants.
gloves, goggles and acid-proof, protective apron. Always add
acid to the water when diluting.
separate from flammable and easily oxidizable
outlets or electrical equipment (e.g. enlargers) are within six
feet of the risk of water splashes.
processing, and there is a wide variation in processes used by
different companies. Color processing can be either done in
trays or in automatic processors.
contains monomethyl-p-aminophenol sulfate, hydroquinone, and
other normal black and white developer components. Color
developers contain a wide variety of chemicals including color
coupling agents, penetrating solvents (such as benzyl alcohol,
ethylene glycol, and ethoxydiglycol), amines, and others.
the hazards of standard black and white developers.
white developers. Para-phenylene diamine, and its dimethyl and
diethyl derivatives, are known to be highly toxic by skin contact
and absorption, inhalation, and ingestion. They can cause very
severe skin irritation, allergies and poisoning. Color
developers have also been linked to lichen planus, an
inflammatory skin disease characterized by reddish pimples which
can spread to form rough scaly patches. Recent color developing
agents such as 4-amino-N-ethyl-N-[P-methane-
sulfonamidoethyl]-m-toluidine sesquisulfate monohydrate and
4-amino-3-methyl-N-ethyl-N-[,3-hydroxyethyl]-aniline sulfate are
supposedly less hazardous, but still can cause skin irritation
borane, the various ethanolamines, etc. are strong sensitizers,
as well as skin and respiratory irritants.
temperature, the elevated temperatures used in color processing
can increase the amount of solvent vapors in the air. The
solvents are usually skin and eye irritants.