Photography Safety

The chemicals and processes used in photographic developing can pose a variety of hazards.  Specfic hazards and ways to mitigate these are described below.

Black-and-White Photographic Processing

Many chemicals are used in black and white photographic processing. Film is usually developed in closed canisters.  Print is processed in trays with successive developing baths, stop baths, fixing baths, and rinse steps.  Other treatments include hardeners, toners, reducers, intensifiers, and hypo eliminators. 

Mixing Photochemicals

Photochemicals can be purchased in liquid or powder form.

Hazards

• Developer solutions and powders often have high concentrations of alkaline metals. Glacial acetic acid is used in making the stop bath. Both are corrosive by skin contact, inhalation, and ingestion.
• Powdered photochemicals are easily inhaled before they are mixed. Some of these powders are mutagenic, carcinogenic, teratogenic (capable of causing birth defects), and many are toxic by inhalation, and various pulmonary issues may result. 
• If mixed with acid, heated, or cross-contaminated with other photo processing baths, photochemicals may generate toxic gases like hydrogen selenide, hydrogen sulfide, hydrogen cyanide, (exposure to these gases may be fatal) and others.

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 liquid photochemicals whenever possible, rather than mixing developing powders to prevent inhalation of dust.  Pregnant women in particular should avoid exposure to powdered developer.
• Use tongs, rather than bare hands, to reach into baths and to handle materials removed from baths.
• When mixing powdered developers, use local exhaust ventilation. If local exhaust ventilation is unavailable and you think you may need respirator protection, please contact EH&S (respirators@umass.edu) for evaluation of your process and assistance with selection and fit-testing of appropriate respiratory protection. 
• Wear full PPE (gloves, chemical splash goggles and protective apron or lab coats) when mixing concentrated photochemicals. 
• Always add any acid to water, never the reverse. 
• Store concentrated acids and other corrosive chemicals on low shelves so as to reduce the chance of face or eye damage in case of breakage and splashing.
• Do not store photographic solutions in glass containers.
• Use of corrosive materials and photochemicals should only occur in locations where there is immediate access (i.e., within 50 ft.) to eyewashes and drench showers.

Developing Baths

Hydroquinone, phenidone, and monomethyl para-aminophenol sulfate are the most common developers. There are other developers used for special purposes. Developing baths usually include an accelerator component (often sodium carbonate or borax), a preservative (sodium sulfite), and a restrainer or anti-fogging agent (potassium bromide).

Hazards

• Developers are skin and eye irritants, as well as strong sensitizers. 
  • Hydroquinone can depigment the skin or eye, can otherwise injure the eye after five or more years of repeated exposure, and is a mutagen.
  • Phenidone is slightly toxic by skin contact.
  • Monomethyl-p-aminophenol sulfate has been known to cause several skin problems, and allergies to it are common. 
  • Absorption of some developers through the skin is severely poisonous (e.g., catechol, pyrogallic acid). 
• Most developers are moderately to highly toxic by ingestion.
  • Ingestion of about a tablespoon of hydroquinone, pyrocatechol, or monomethyl-p-aminophenol sulfate could be fatal for adults.
  • Symptoms after ingestion may include ringing in the ears (tinnitus), muscle spasms (i.e., twitching), nausea, headache, dizziness, delirium, shortness of breath, cyanosis (turning blue from lack of oxygen) due to methemoglobinemia, coma, and convulsions.
• Para-phenylene diamine and some of its derivatives are highly toxic by skin absorption, inhalation, and ingestion. They cause very severe skin allergies.
• Sodium hydroxide, sodium carbonate, and other alkali salt accelerators (especially in concentrated solutions) are highly corrosive. Ingestion and contact with the skin is hazardous.
• Potassium bromide is toxic by ingestion, inhalation, and skin absorption.  Symptoms of repeated exposure include somnolence, depression, lack of coordination, mental confusion, hallucinations, and skin rashes.
• If inhaled or ingested, sodium sulfite can cause gastric upset, diarrhea, colic, circulatory problems, and depression of the central nervous system.  It is not appreciably toxic by skin contact.  If heated or dissolved in water or acid, it decomposes and emits sulfur dioxide, which is a highly irritating gas.

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 tongs, rather than bare hands, to reach into developer baths.
• Ensure that PPE is worn appropriate to the task.  Ensure that gloves worn afford protection to the materials in use. Chemical splash goggles must be worn for all work with corrosive materials.  Lab coats, smocks, or other protective clothing must be worn for activities where a splash hazard is likely.
• In the case of a skin or eye exposure, immediately rinse with lots of water for approximately 15 minutes. Seek medical attention if irritation persists or if eyes are affected. Seek medical attention if you develop skin irritation or other signs of allergic response to materials, and stop using the materials immediately.
• Use of corrosive materials and developers should only occur in locations where there is immediate access (i.e., within 50 ft.) to eyewashes and drench showers.
• Do not use para-phenylene diamine or its derivatives if at all possible.

Stop Baths and Fixer

Stop baths are most often a weak solution of acetic acid. Potassium chrome alum is sometimes used in stop baths as a hardener. Fixing baths consist of a fixing agent (sodium thiosulfate, "hypo"), and a preservative (sodium sulfite and sodium bisulfite).  They sometimes also contain a hardener like alum (potassium aluminum sulfate) and a buffer such as boric acid.

Hazards

• Concentrated acetic acid is highly toxic to the skin, intestines, and respiratory tract.  It can cause dermatitis, ulcers, and irritates the mucous membranes.  The final stop bath is slightly toxic to the skin.  Repeated exposure to acetic acid vapors by inhalation, even from the stop bath, may cause chronic bronchitis.
• Potassium chrome alum or chrome alum (potassium chromium sulfate) can cause dermatitis and allergies, as it is moderately toxic to the skin and respiratory tract.
• Powdered sodium thiosulfate is not significantly toxic to the skin, but purges the bowels upon ingestion.  When heated or long-standing in solution, it can decompose to produce highly toxic sulfur dioxide, which can cause chronic lung problems if inhaled. Sulfur dioxide is particularly harmful for asthmatics.
• Sodium bisulfite also forms sulfur dioxide when decomposed if the fixing bath contains boric acid, or if acetic acid contaminates the fixing bath on the surface of the print.
• Boric acid is moderately toxic by ingestion or inhalation, and slightly toxic by skin contact. However, contact with burned or abraded skin can be highly toxic.

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 tongs, rather than bare hands, to reach into baths and to handle materials removed from baths.
• Adequate ventilation is required in all darkrooms to control counts of  acetic acid and sulfur dioxide vapors produced by the stop and fixer baths. If local exhaust ventilation is unavailable/inadequate and you think you may need respirator protection, please contact EH&S (respirators@umass.edu) for evaluation of your process and assistance with selection and fit-testing of appropriate respiratory protection. 
• Wear  appropriate PPE: gloves, goggles and protective aprons or lab coats.
• Use of corrosive materials and photochemicals should only occur in locations where there is immediate access (i.e., within 50 ft.) to eyewashes and drench showers.
• Cover all baths when not in use to prevent the evaporation of toxic vapors.

Intensifiers and Reducers

Intensification or reduction are common after-treatments for negatives and prints. Common intensifiers are hydrochloric acid with potassium dichromate, or potassium chlorochromate. Many intensifiers (such as: Monckhoven's intensifier; mercuric chloride followed by a silver nitrate/potassium cyanide solution; mercuric iodide/sodium sulfite; and uranium nitrate) are older and no longer used due to the unnecessary hazards associated with these materials.

Farmer's reducer, which is made up of potassium ferricyanide and sodium thiosulfate (“hypo”), is used in the reduction of negatives.  Historically, reduction has been done with iodine/potassium cyanide, ammonium persulfate, and potassium permanganate/sulfuric acid. The health and fire hazards associated with these materials is unnecessary when safer options are available.

Hazards

• Potassium dichromate and potassium chlorochromate are suspected carcinogens, and can cause skin allergies and ulceration. If adding acid or heating, potassium chlorochromate can release highly toxic chlorine gas.
• Sodium or potassium cyanide is extremely toxic by all routes of exposure. Adding acid to cyanide forms extremely toxic hydrogen cyanide gas, which can kill a human in less than 10 minutes.
• Potassium ferricyanide is slightly toxic on its own. However, it will release hydrogen cyanide gas when heated, if hot acid is added, or if exposed to strong ultraviolet light (e.g., carbon arcs). For instance, treating Farmer's reducer with acid has been known to lead to cyanide poisoning.
• Concentrated hydrochloric acid is corrosive; if diluted, it is still a skin and eye irritant.
• Uranium intensifiers are radioactive, and are especially hazardous to the kidneys.
• Mercury compounds are toxic by all routes of exposure, and are known to cause brain damage.  
• Potassium permanganate and ammonium persulfate are strong oxidizers that may cause fires or explosions when they contact solvents or other organic materials.

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 tongs, rather than bare hands, to reach into baths and to handle materials removed from baths.
• Chromium intensifiers are the safest intensifiers, even though they are probable human carcinogens.  Appropriate PPE (gloves, chemical splash goggles, lab coats, and protective aprons) should be worn when preparing and using these.
• Use of corrosive materials and photochemicals should only occur in locations where there is immediate access (i.e., within 50 ft.) to eyewashes and drench showers.
• Mixing intensifier powders should be done with local exhaust ventilation. If local exhaust ventilation is unavailable and you think you may need respirator protection, please contact EH&S (respirators@umass.edu) for evaluation of your process and assistance with selection and fit-testing of appropriate respiratory protection. 
• Do not expose potassium chlorochromate to acid or heat.
• Do not use mercury, cyanide or uranium intensifiers because of their high or extreme toxicity.
• Do not use cyanide reducers because of their extreme toxicity.
• The least hazardous reducer to use is Farmer's reducer.  Do not expose Farmer's reducer to acid, ultraviolet light, or heat.
• Ensure that spent materials are handled as hazardous waste. Please refer to the Hazardous Waste Management video for more information and consult us at askehs@umass.edu if you have specific hazardous waste questions.

Toners

Toning a print involves replacing silver with another metal, such as selenium, gold, iron, platinum, or uranium.  Sometimes toning involves replacing silver metal with brown silver sulfide.  

Hazards

• Gold and platinum salts are strong sensitizers: they can produce allergic skin reactions and asthma.
• Highly toxic hydrogen sulfide gas is generated during sulfide toning, or when the toner is treated with acid. Hydrogen sulfide gas can be fatal 1 to 4 hours after exposure, but loss of consciousness may be immediate.
• Selenium can damage the kidneys and is a skin and eye irritant.  Treatment of selenium salts with acid may release highly toxic hydrogen selenide gas, exposure to which can be fatal.  Selenium toners also give off large amounts of sulfur dioxide gas (a strong irritant to the respiratory tract, and can be dangerous for people with asthma or bronchitis).
• Thiourea is a probable human carcinogen.

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 tongs, rather than bare hands, to reach into baths and to handle materials removed from baths.
• As it is a likely carcinogen, avoid thiourea whenever possible.
• Make sure that sulfide or selenium toners are not contaminated with acids.  For instance, make sure you rinse a print thoroughly after bleaching in an acid solution and before dipping it in the sulfide developer.
• Wear appropriate PPE (gloves, goggles, lab coats, and protective aprons).  
• Use of corrosive materials and photochemicals should only occur in locations where there is immediate access (i.e., within 50 ft.) to eyewashes and drench showers.
• Use toning solutions with local exhaust ventilation. If local exhaust ventilation is unavailable and you think you may need respirator protection, please contact EH&S (respirators@umass.edu) for evaluation of your process and assistance with selection and fit-testing of appropriate respiratory protection.

Other Hazards

Many additional chemicals are also used in black-and-white photo processing, including a variety of oxidizing agents as hypo eliminators (e.g., bleaches, potassium permanganate, hydrogen peroxide and ammonia, potassium persulfate), silver nitrate to test for residual hypo, sodium sulfide to test for residual silver, formaldehyde (a pre-hardener), solvents such as methyl chloroform and freons for film and print cleaning, as well as concentrated acids to clean trays. Electrical outlets and equipment present electrical hazards in darkrooms due to the risk of splashing water.

Hazards

• When mixed with potassium permanganate or potassium dichromate, concentrated sulfuric acid produces highly corrosive acids.
• Hypochlorite bleaches release highly toxic chlorine gas when heating or adding acid.
• Potassium persulfate and other materials used as hypo eliminators are oxidizers, and may ignite when contacting flammable or organic chemicals, like many solvents.  Most are also skin and eye irritants.

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 tongs, rather than bare hands, to reach into baths and to handle materials removed from baths.
• Wear appropriate PPE (gloves, chemical splash goggles, lab coat, and acid-proof apron) when handling cleaning acids. Always add acid to the water, never the reverse, when diluting.
• Use of corrosive materials and photochemicals should only occur in locations where there is immediate access (i.e., within 50 ft.) to eyewashes and drench showers.
• Separate potassium persulfate and other strong oxidizing agents from flammable and oxidizable substances.
• Do not heat or add acid to hypochlorite bleaches, as this will generate highly toxic gases.
• Install ground fault interrupters (GFCIs) whenever electrical outlets or electrical equipment (e.g. enlargers) are within six feet of baths where there is a splash risk.

Color Processing

Color processing is much more complicated than black and white 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.

Color Developing Baths

The first developer in color transparency processing usually contains monomethyl-p-aminophenol sulfate, hydroquinone, and other components normal in black and white developers.  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.

Hazards

• In general, color developers are more hazardous than black and 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 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-[1,3-hydroxyethyl]-aniline sulfate) are supposedly less hazardous, but still can cause skin irritation and allergies.
• Although many of the solvents are not very volatile at room 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.
• Most amines (including ethylene diamine, tertiary-butylamine borane, the various ethanolamines, etc.) are strong sensitizers, as well as skin and respiratory irritants.

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 tongs, rather than bare hands, to reach into baths and to handle materials removed from baths.
• Wear appropriate PPE (gloves, chemical splash goggles, lab coat, and acid-proof apron) when handling color developers. Wash gloves with an acid-type hand cleaner, and then water before removing them.
• Use of corrosive materials and photochemicals should only occur in locations where there is immediate access (i.e., within 50 ft.) to eyewashes and drench showers.
• When mixing powders, use local exhaust ventilation. If local exhaust ventilation is unavailable and you think you may need respirator protection, please contact EH&S (respirators@umass.edu) for evaluation of your process and assistance with selection and fit-testing of appropriate respiratory protection. 
• Color processing needs stronger ventilation compared to black and white processing due to the use of solvents and other toxic components at elevated temperatures.
• Seek medical attention if you develop skin irritation or other signs of allergic response to materials and stop using the materials immediately.

Color Processing: Bleaching, Fixing, and Other Steps

Many of the chemicals used in other steps of color processing are essentially the same as those used for black and white processing. Bleaching uses a number of chemicals, including ammonium thiocyanate, potassium bromide, potassium ferricyanide, and acids. Chemicals found in prehardeners and stabilizers include succinaldehyde and formaldehyde; neutralizers can contain hydroxylamine sulfate, acetic acid, and other acids.

Hazards

• Hydroxylamine sulfate is a suspected teratogen (capable of causing birth defects) in humans since it is a teratogen in animals.  It is also a skin and eye irritant.
• Formaldehyde is moderately toxic by skin contact, and highly toxic by inhalation and ingestion.  It is a skin, eye and respiratory irritant, and strong sensitizer, and is a human carcinogen.  Formaldehyde solutions contain some methanol, which is highly toxic by ingestion.
• Succinaldehyde is similar in toxicity to formaldehyde, but is not a strong sensitizer or carcinogen.
• Potassium ferricyanide will release hydrogen cyanide gas if heated, if hot acid is added, or if exposed to strong ultraviolet radiation.
• Concentrated acids, such as glacial acetic acid, hydrobromic acid, sulfamic acid and p-toluenesulfonic acids are corrosive by skin contact, inhalation and ingestion.
• Acid solutions, if they contain sulfites or bisulfites (e.g., neutralizing solutions), can release sulfur dioxide upon standing.  If acid is carried over on the negative or transparency from one step to another step containing sulfites or bisulfites, then sulfur dioxide can be formed.

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. 
• Wear appropriate PPE (gloves, chemical splash goggles, lab coat, and protective apron) when mixing and handling color processing chemicals.
• Use tongs, rather than bare hands, to reach into baths and to handle materials removed from baths.
• Use of corrosive materials and photochemicals should only occur in locations where there is immediate access (i.e., within 50 ft.) to eyewashes and drench showers.
• When diluting solutions containing concentrated acids, always add the acid to the water, never the reverse. 
• Use premixed solutions whenever possible.
• Use local exhaust ventilation when mixing chemicals for color processing. If local exhaust ventilation is unavailable and you think you may need respirator protection, please contact EH&S (respirators@umass.edu) for evaluation of your process and assistance with selection and fit-testing of appropriate respiratory protection. 
• Avoid color processes using formaldehyde, if possible.
• A water rinse step is recommended between acid bleach steps and fixing steps to minimize the production of sulfur dioxide gas.
• Do not add acid to solutions containing potassium ferricyanide or thiocyanate salts.
• Control the temperature carefully according to manufacturer's recommendations to reduce emissions of toxic gases and vapors.