Photography - Safe Work Practice Manual

Safe Work Practices Manual

Fine Arts Studio - Photography


  • Regularly review the Safe Work Practices Manual-this is an important resource.
  • Know the material you are working with and read the WHMIS labels and information sheets to ascertain the proper safety precautions you should take. These are located outside the entrance to the main darkroom.
  • For example you may need to wear a respirator and work in a ventilated environment based on the information provided with this material.
  • Wear the appropriate Personal Protection Equipment when working in the studios. Including chemical aprons or lab coats, nitrile gloves, chemical splash goggles and solid toe covering shoes when working with photographic chemicals.
  • Photo chemicals are controlled substances, do not spread them to your living space. Wash your hands, and wear chemical proof garments as suggested above.
  • If you are unsure about a process or procedure consult the safe work manual, a Technician and your Instructor before starting.
  • All placement of art outside the studio classroom must be approved by OH&S through the completion of the Art Placement Form.
  • This form is on the OH&S website of the university and must be completed five days prior to the installation of your work.
  • Doors to studios must be kept closed-do not prop open.
  • Never pass or the lock combination to anyone-this is for your protection and the protection of studio facilities.
  • Wear personal listening devices in all Studio Classrooms when working after class hours. Other students may need the quiet to concentrate.


  • Do not block fire exits and fire-fighting equipment.
  • Store materials in designated storage areas or in your studio spaces.
  • Keep your studio facilities and classrooms clean and tidy.
  • Respect your work and the work of others.
  • Keep all disposal bins tidy with no projecting articles.
  • Clean up spills immediately in order to avoid a slipping hazard.
  • Remove large projects immediately after they have been graded to open up space to make more work.
  • Keep aisles, walkways and stairs clear.
  • Clean and put away all tools and materials in designated storage areas when job is done, and at the end of each workday.
  • Wear the appropriate Personal Protection Equipment when working in Art Studios and Workshops.
  • Sweep floors, equipment, counters, and tables after completion of tasks and at the end of every workday.
  • Avoid causing trip hazards with extension cords and air hoses.
  • Be aware of the impact of your work on the work of others.

Each person in the School of Fine Arts is responsible and accountable for his/her own safety performance. It is important that each person understand that he/she is also expected to work in a manner that will not cause harm to any other person within the University community. Art materials can affect the body in various ways. There are three major routes of entry: inhalation, ingestion and skin contact.

  1. Inhalation
    • The most common ways that foreign substances enter the body are from vapors, fumes, dust, gases or mists that can be inhaled into the respiratory system. The substances may damage the nose, mouth, and upper respiratory tract, lungs or be absorbed into the bloodstream and travel to other organs in the body.
  2. Ingestion
    • Substances may be accidentally or willingly ingested through the contamination of food, drinks, cigarettes and hands. These substances may affect the mouth, throat and/or stomach or be absorbed into the bloodstream.
  3. Skin Contact
    • Substances may attack or destroy the natural protective barriers of the skin, damaging the skin itself, and enabling toxic chemicals to enter the bloodstream, where they are carried to various organs of the body.

It is imperative that eating and/or drinking do not occur in any work area.

All students are required to participate in the Safe Work Practices. This includes participation in training and instructional workshops, reading the information sheets that accompany the training sessions, and signing off on their understanding of the information before beginning work in the studio facilities.


Once the training requirement has been met Students are allowed to work in the Sculpture Facilities W840 according to the following schedule:
8:30 am – 8:00 pm Monday–Thursday
9:00 am – 5:00 pm Friday
8:30 am – 4:30 pm Saturday

Summer Schedule
Monday -Friday
8:30 am –4:30 pm

It is the responsibility of every person in the area to be aware of his or her surroundings, which in turn will create a safe working environment. Particular attention should be paid to the following:

  1. Telephone: located inside the studio at the exit. Emergency numbers are posted beside each telephone.
  2. First Aid Kits: located in each area and are clearly marked. These are for emergency first aid procedures only. Do not use supplies for any other use.
  3. Eye Wash Stations: located in each area and are clearly marked. Eye wash stations are tested every month, by the department Safety Representative.
  4. Fire Extinguishers: located in every working area.

The following materials and substances cannot be used in student projects:ammunition orexplosives, flammable liquids, biohazardous material or waste.

WHMIS information sheets and proper labeling according to WHMIS regulations must accompany all controlled products. WHMIS training is provided by OH&S, as a student you must complete the WHMIS Online Training Course offered through OH&S on Moodle.

Safety Data Sheets are provided in all studios for all controlled products supplied by the Department to support instruction.

Controlled products for your personal use must also have appropriate WHMIS labels and accompanying SDS information sheets.

  • All containers must be labeled (including harmless items like distilled water). The label should contain the proper name of the material (Turpenoid, Varsol) and the name of the user if appropriate, a statement of hazards should also be listed.
  • Do not use material from unlabeled containers. The need for adequate labeling extends far beyond the immediate individual user, as they may not be present if the container spills or breaks.
  • It is important that no unidentified materials are left in unlabeled containers, jars, or bottles. Proper labeling is important since it is difficult and costly to dispose of unlabeled chemicals.

Each individual has the responsibility for seeing that waste chemicals are safely collected, identified and stored for disposal, and that anyone involved is fully advised of the need for any special methods or facilities for proper disposal.

Handling of Waste

Chemicals are everywhere: they can be found in animals, plants and water as well as in many commercially available products including medicines, detergents, paints,and foods. The risk may be low, but present. In order to keep the risk to a minimum, all chemical waste must be disposed of properly. Once a material is declared a waste, the first responsibility for guiding its proper disposal rests with the worker. He or she is in the best position to know the degree of hazard posed by the material they have used and must provide sufficient information to fit it into the correct channel for disposal.

Some Acids and Bases:

The following acids and bases have been approved for drain disposal while flushing drain with water, if the pH range is between 3 and 11 (prior to draining).

Sulfuric acid, hydrochloric acid, phosphoric acid, sodium hydroxide, potassium hydroxide.

Any chemical which qualifies as a hazardous waste must be collected for proper disposal through OH&S.A waste may be designated as a hazardous waste if it meets one of the following criteria:

  1. Acute hazardous waste is a waste which has been found to be fatal in humans in low doses or, in the absence of data on humans, has been found to have, in laboratory animals:
    • An oral LD50 (Lethal Dose of 50% of the test subjects) of less than 50 mg/kg.
    • An inhalation LC50 (Lethal Concentration) of less than 2 mg/l, or
    • A dermal LD50 of less than 200 mg/kg.
  2. A waste is hazardous if it contains any of the toxic constituents listed in the regulations.
  3. A waste is hazardous if it exhibits any of the following characteristics:
    • Ignitability
    • Corrosivity
    • Reactivity
    • Toxicity *
    • Sharpness
  4. Each Studio generating chemical waste in the Department has a designated location within the room for waste accumulation.
  5. Hazardous Waste Disposal containers are located by the sinks in most studios. As well sharps containers are located in various studios for the safe disposal of glass, knives or saw blades.

All workplace hazardous materials must be identified and disposed of according to Provincial Regulations. No substance that may affect the Environment, Plant, Animal, or Human Life can be disposed of in the garbage or flushed down the sewer system. Consult with a Technician before you act.

Effective ventilation is the best method for controlling contaminants generated and released into the studio atmosphere. There are two basic types of ventilation: general and local exhaust. Local exhaust ventilation is required when working in:

Painting Studio W817
Metal Shop W840
Advanced Studio W823
Kiln Room W890D
Wood Shop W840A
Clay Mixing/ SlurryRoom 890A

Spray Booths are located in W840 + W520, use these when spraying fixative to drawings or when using spray paint. If the contaminant is highly toxic or large amounts of the toxic material are produced a respirator must also be worn.

As a result of the hazard assessment performed by the Technical Staff of the Department of Art working alone is not permitted. All work planned after 8:00 pm must be done with another student. Any Students found working alone in any studio area will be asked to leave the facility by Security personnel. The buddy system should now be enforced in all of the following workspaces: W817, W823, W869, W871, W890, A, B, C +D, W520,L804, W844, W842, and W748 A-K. Excerpt from Art Safety Policy (1992);

In addition, students working after hours are required to have a buddy present. A buddy is another student who is enrolled in and cognizant of the School of Fine Arts Safety Policy. The buddy must remain within the same studio at all times.

The University of Lethbridge now has a Working Alone Safely Login that informs Security that an individual is working alone on campus. All Faculty,Staff, and Students are asked to use this system to login and out with security when they are on campus after regular hours. This policy was developed through the guidelines found in the booklet “Working Alone Safely: A Guide for Employers and Employees” as developed by Alberta Human Resources and Employment.


In the event of fire, please phone the following EMERGENCY number immediately: 911 or 403-329-2345.

  1. Action to be taken (R.E.A.C.T.):
  2. Remove those in danger.
  3. Ensure the room is closed. This step will confine a fire to the room of origin. This will also prevent the spread of smoke and toxic gases.
  4. Activate the fire alarm. This will occur automatically with smoke and heat detection equipment. There is nothing wrong with calling the Fire Department for assistance and providing details of the fire.
  5. Call the Fire Department. 911 or 329-2345. A person should be designated to call the Fire Department even though the building alarm system is automatically connected to the Fire Department.
  6. Try to extinguish or control the fire. If there is any doubt in the mind of the person(s) attempting to extinguish the fire regarding their ability to do so, then confine the fire to the room of origin by closing the door.
  7. Evacuate.
  8. Keep people from re-entering the building until directed to do so by the Building Fire Warden of Campus Security.

Air Contamination

Should you smell any foreign or unrecognized odors, please phone the following EMERGENCY number immediately: 403-329-2345.

What to report:

  1. The location of the odor.
  2. Time the odor was first apparent.
  3. Any physical symptoms experienced by persons in the affected area, ie. headache, feeling of nausea.
  4. Any information suggesting the odor's origin.

Open any windows or doors to attempt to dilute the polluted air with fresh outside air. Stay out of the affected area and await further instruction by safety personnel.

Chemical Spills

Should a chemical spill occur in your area please phone the following EMERGENCY number immediately: 403-329-2345. For minor chemicals spills contact Technical Staff in W840 for assistance. Use copious quantities of water when cleaning up chemicals.

What to report:

  • The location of the spill and any evidence that tells what the chemical could be, ie. an empty bleach bottle lying on the floor indicating the substance may be bleach.
  • Any odor, ie. a strong smell of ammonia.
  • Any visible chemical reaction that may be occurring, ie. a substance bubbling on the floor.

When proper personnel have been notified, no one should enter the contaminated area. If an odor is present, open a window and post a guard outside the odorous area keeping untrained persons away. NO ATTEMPT SHOULD BE MADE TO CLEAN UP THE SPILL. Await arrival of emergency personnel.

Personal Protection Equipment

There are times when exposure to toxic materials cannot be prevented, and as such any person working in the area must wear the appropriate personal protective equipment. Contact the Technician, your Professor, or OHS for assistance in selecting the correct PPE. It is not only important that the correct PPE is worn but that the equipment fit properly. For instance ,respirators must have a mask to face seal and facial hair prevents a tight seal.

For detail information please refer to Info sheets in the Workplace Safety Manual located in W840.

  • Prescription lenses and sport glasses are not an acceptable substitute for proper, required Industrial safety eye protection.
  • Contact lens should not be worn in Art Studio Environments. Contact lens may trap or absorb particles or gases causing eye irritation or blindness.
  • CSA approved eye protection must be worn when working in W840 and elsewhere when the activity demands it.
  • Eye protection should fit properly, with or without prescription lens.
  • Return glasses to the proper storage rack face up to avoid scratching lens.
  • In this storage rack you will find a variety of styles pick the one that fits you best.
  • There are two common types of hearing protection: earplugs or earmuffs.
  • One or both types must be used when working in W840 and W890B (grinding room) and at all times when equipment is operating.
  • These studio workshops are high noise areas and hearing protection is a must even if you are not the one making the noise.
  • Hearing loss, which normally occurs over an extended period of time, is one concern in high noise areas. The immediate effect of high noise areas is fatigue-when we are tired we make mistakes, some of which could be serious.
  • Students are required to wear good solid shoes when working in Art Studio. Leather shoes with closed toes are best. These protect your feet from most substances used in studios-for example, spills: photo chemicals, acids, and paints. Open toed sandals should not be worn in any studio, and are not permitted in W840.
  • If you have safety boots wear them and if you know you are going to live in these studios buy some safety footwear.
  • Employees must wear safety footwear in the above areas and in the performance of the majority of their duties.
  • Dust masks must be worn in W840, W840A, and W890 A, B, and C when the activities in these areas are dust producing.
  • Local ventilation and air extraction equipment must be utilized in the above studios depending on the nature of your activity.
  • Spray Booths are located in W840 + W520, use these when spraying fixative to drawings or when using spray paint.
  • If the contaminant is highly toxic or large amounts of the toxic material are produced a respirator must also be worn.

Due to the variety of studio activities you must consider further personal protection that may take many different forms such as leather gloves, nitrile gloves, leather/chemical aprons etc.

Generally the following rules apply when working in studios and shops:


  • All rings, bracelets, necklaces, and watches should be removed. Long hair must be tied firmly back and tuck in. Short sleeves should be worn when working in the wood shop and shirttails must be tucked in.
  • If you bend over nothing should fall away from your body.
  • When working with metal or hot processes long sleeves should be worn, and clothing should be made of natural fibers. Synthetic fibers melt onto the skin and can cause severe burns.
  • Shirttails should not be tucked in when working with hot processes, no cuffs, and pocket flaps should be closed. You want any hot particle to be able to pass through your clothing and not to become trapped against your skin.
  • Shorts and open-toed shoes or sandals should not be worn in the studios. You must keep in mind that many of the products you will use are absorbed through the skin, and could be corrosive.
  • Wash hands and arms thoroughly before leaving the studios after working with potentially hazardous material and before eating, drinking, smoking, etc.

This space will operate on a one-week rotating schedule, and it is your responsibility to schedule your time in this space. At the end of the exhibition period the following procedure must be followed:

  • Get the paint kit from technicians. In this kit you will find the following supplies:
  • Paint Brush, Roller sleeve and handle, pole sander and sand paper, Extension Pole, Wall Filler, putty knife, Tape, White Latex paint, Paint Tray and drop cloths, brush, and roller spinner.
  • Lay down the drop cloths tight to the walls, if necessary tape these down with painters tape. They should overlap each other by 24”.
  • Remove all nails and fastening devices, with pole sander lightly sand the walls, smoothing out the dimple caused by your nails.
  • Prepare a small quantity of wall filler and apply leanly to all nail holes.
  • When this is dry lightly sand the walls again taking care to make the walls as smooth as possible.
  • Stir your paint well and only use the latex paint provided.
  • Fill the paint tray with a moderate quantity of paint working only on the drop clothes.
  • With a paintbrush first apply a brush coat on all filled areas, then carefully cut in the edges of the walls. Do not paint concrete, floors, baseboards, or electrical outlets.
  • Once you have finished cutting in use the roller to apply a light even coat of white latex paint to the walls.
  • After you have completed the painting scrap excess paint from roller into tray, with a brush, clean paint tray returning excess paint to paint ca. Roll or fold up your drop cloths and sweep the area before returning paint kit to W840.
  • Return all used painting equipment to W840 and carefully remove the roller sleeve and thoroughly rinse it in the sink making sure all paint is washed out of roller and paintbrush.
  • Using the paint spinner in the sink fit roller sleeve over end of spinner and spin roller to remove excess water. Stand damp roller sleeve upright for finally drying.
  • Using the paint spinner, place brush handle into clamp and spin to remove excess water. Smooth out the bristle while brush is still damp and lay brush flat to dry or hang on wall over sink.
  • You may be asked by your instructor not to use any personal listening devices during class hours. If this is the case please follow the directions given you.
  • Do not work alone in photography studio area after 8:00 pm. you must have someone working in the same classroom with you.
  • Do not block fire exits and fire fighting equipment.
  • Store materials in designated storage areas or in your locker or studio space.
  • Keep your darkroom facilities and photography studios clean and tidy. Clean up spills immediately in order to avoid a slipping hazard.Keep all disposal bins tidy with no projecting articles.
  • Respect your work and the work of others.
  • In the photo lab chemicals spills are common. Please wash down counters and sinks after use. Use copious amounts of water to rinse sinks and scrub trays.
  • Photo chemicals will damage your work and the final work of others-cleanliness is paramount in Photo Studios.
  • Photo chemicals are hard on your body keep them controlled and do not spread chemicals to dry work areas. They will contaminate yourself and others.
  • Absolutely no eating or drinking in any photo area.
  • If you work in photo for long stretches at a time plan regular fresh air breaks, leave the studio wash your hands and walk around a bit. Your work will go better and you will be better.
  • Use nitrile gloves with all chemical use and tongs when processing prints.
  • Enlarger areas in darkroom are dry zones-do not contaminate with chemicals.
  • Processing equipment in darkrooms is very specialized; do not over tighten adjustment knobs, and do not remove lens boards from enlargers.
  • Do not bang or rap film processing tanks against the edge of sinks or counters. Rap sharply with the flat bottom of the tank on flat surfaces only.
  • When focusing you negative do not rest the weight of your body against focus adjustment knobs or these will break.
  • Use clean leather gloves if you need to handle hot lighting equipment.
  • Do not overload circuits by plugging all your studio lights into one outlet, or circuit. Plug studio lights into power bars then use outlets on opposite walls to avoid over loading electrical circuits.
  • Studio lights produce a lot of heat-never leave lights on unattended.
  • Do not use flammable materials on or near studio lighting equipment.
  • Do not place electrical cords on or near hot lights. To avoid this possibility arrange your time so that all equipment has a chance to cool down before returning to proper storage units.
  • All quartz lights must be used with the protective mesh in place to avoid potential burn and flying glass hazards should bulbs break.
  • Avoid trip hazards when arranging lighting set-ups; remember that equipment that falls will likely break.
  • Make all lighting set-ups with a view to safety as well as aesthetics, tape cords down and be aware of all safety hazards in lighting studios.

Black and White Processing

A wide variety of chemicals are used in black and white 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.

Photochemical can be bought in liquid form, which only need diluting, or powder form, which need dissolving and diluting.


  • Developer solutions and powders are often highly alkaline and glacial acetic acid, used in making the stop bath, is also corrosive by skin contact, inhalation and ingestion.
  • Developer powders are toxic by inhalation, and toxic by skin contact, due to the alkali and developers themselves (see Developing Baths below).
  • Developers may cause methemoglobinemia, an acute anemia resulting from converting the iron of hemoglobin into a form that cannot transport oxygen.


  • Use liquid chemistry whenever possible, rather than mixing developing powders. Pregnant women, in particular, should not be exposed to powdered developer.
  • When mixing powdered developers, use local exhaust ventilation.
  • Wear gloves, goggles and protective apron when mixing concentrated photochemical.
  • Always add any acid to water, never the reverse.
  • An eyewash fountain and emergency shower facilities should be available where the photochemical 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.
  • 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.
  • Label all solutions carefully so as not to ingest solutions accidentally.


  • The most commonly used developers are hydroquinone, mono-methyl para-aminophenol sulfate, and phenidone.
  • 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.


  • Developers are skin and eye irritants, and in many cases 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 slightly toxic by skin contact.
  • Most developers are moderately toxic by ingestion, 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 occur. Para-phenylene diamine and some of its derivatives are highly toxic by skin contact, inhalation, and ingestion. They cause very severe skin allergies and can be absorbed through the skin.
  • Sodium hydroxide, sodium carbonate, and other alkalis used as accelerators are highly corrosive by skin contact or ingestion. This is a particular problem with the pure alkali or with concentrated stock solutions.
  • Potassium bromide is moderately toxic by inhalation or ingestion and slightly toxic by skin contact. Symptoms of systemic poisoning include somnolence, depression, and 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.
  • Sodium sulfite is moderately toxic by ingestion or inhalation, 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.


  • Do not put your bare hands in developer baths. Use tongs and gloves 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.
  • Do not use para-phenylene diamine or its derivatives if at all possible.
  • Stop baths are usually weak solutions of acetic acid. Acetic acid is commonly available as pure glacial acetic acid or 28% acetic acid. Some stop baths contain potassium chrome alum as a hardener.
  • 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.


  • Acetic acid, in concentrated solutions, is highly toxic by 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.
  • Potassium chrome alum or chrome alum (potassium chromium sulfate) is moderately toxic by skin contact and inhalation, causing dermatitis and allergies.
  • In powder form, sodium thiosulfate is not significantly toxic 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.
  • Sodium bisulfite decomposes to form sulfur dioxide if the fixing bath contains boric acid, or if acetic acid it transferred to the fixing bath on the surface of the print.
  • Alum (potassium aluminum sulfate) is only slightly toxic. It may cause skin allergies or irritation.
  • Boric acid is moderately toxic by ingestion or inhalation and slightly toxic by skin contact (unless the skin is abraded or burned, in which case it can be toxic).


  • All darkrooms require good ventilation to control the level of acetic acid vapors and sulfur dioxide gas produced in photography. Kodak recommends at least 10 air changes per hour. The exhaust duct opening should preferably be located behind and just above the stop bath and fixer trays.
  • Wear gloves and goggles and vinyl apron or lab coat.
  • Cover all baths when not in use to prevent evaporation or release of toxic vapors and gases.


  • A common after-treatment of negatives (and occasionally prints) 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 been done historically with iodine/potassium cyanide, ammonium persulfate, and potassium permanganate/sulfuric acid.


  • Potassium dichromate and potassium chlorochromate are probable human carcinogens, and can cause skin allergies and ulceration. Potassium chlorochromate can release highly toxic chlorine gas if heated or if acid is added.
  • Concentrated hydrochloric acid is corrosive; the diluted acid is a skin and eye irritant.
  • Mercury compounds are moderately toxic by skin contact and may be absorbed through the skin. Uranium intensifiers are radioactive, and are especially hazardous to the kidneys.
  • Sodium or potassium cyanide is extremely toxic by inhalation and ingestion, and moderately toxic by skin contact. Adding acid to cyanide forms extremely toxic hydrogen cyanide gas, which can be rapidly fatal.
  • Potassium ferricyanide, although only slightly toxic by 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.
  • Potassium permanganate and ammonium persulfate are strong oxidizers and may cause fires or explosions in contact with solvents and other organic materials.


  • Chromium intensifiers are probably the least toxic intensifiers, even though they are probable human carcinogens.
  • Gloves and goggles should be worn when preparing and using these intensifiers. Do not expose potassium chlorochromate to acid or heat.
  • Do not use mercury, cyanide or uranium intensifiers, or cyanide reducers because of their high or extreme toxicity.
  • The safest reducer to use is Farmer’s reducer. Do not expose Farmer’s reducer to acid, ultraviolet light, or heat.
  • Toning a print usually involves replacement of silver by 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.


  • Sulfides release toxic hydrogen sulfide gas during toning, or when treated with acid.
  • Selenium is a skin and eye irritant and can cause kidney 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.
  • Gold and platinum salts are strong sensitizers and can produce allergic skin reactions and asthma, particularly in fair-haired people.
  • Thiourea is a probable human carcinogen since it causes cancer in animals.


  • Carry out normal precautions for handling toxic chemicals as described in previous sections. In particular, wear gloves and goggles.
  • Toning solutions must be used with proper exhaust ventilation.
  • Take precautions to make sure that sulfide or selenium toners 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 developer.
  • Avoid thiourea whenever possible because of its probable cancer status.
  • Many other chemicals are also used in black and white 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.
  • Concentrated sulfuric acid, mixed with potassium permanganate or potassium dichromate, produces highly corrosive permanganic and chromic acids.
  • Hypochlorite bleaches can release highly toxic chlorine gas when acid is added, or if heated.
  • Potassium persulfate and other oxidizing agents used as hypo 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.


  • Cleaning acids should be handled with great care. Wear gloves, goggles and acid-proof, protective apron. Always add acid to the water when diluting.
  • Keep potassium persulfate and other strong oxidizingagents separate from flammable and easily oxidizable substances.
  • Install ground fault interrupters (GFCIs) whenever electrical outlets or electrical equipment (e.g. enlargers) are within six feet of the risk of water splashes.



Hazard Assessment



Working alone

Serious EC: emergency phone
AC: no working alone, buddy system
+ register with Security

Fumes & vapours

Serious EC: Sink exhaust system AC: training, safe work practices
PE: respirator when mixing chemicals

Eye strain - low light

Serious EC: safe light environment
AC: take breaks

Chemical exposure

Serious EC: exhaust system, air exchange system
PE: gloves, print tongs, apron/lab coat

Repetitive strain

Moderate AC: take rest periods, shift work positions, flex body parts to release strain


Moderate AC: training, safe work practices, use proper knives

Light radiation - lighting studio

Moderate AC: training, safe work practices

Slips / falls

Low light / wet darkroom

Serious AC: housekeeping, training, safe work practices

EC= Environmental Controls(such as ventilation)
AC= Administrative Controls(such as policies, manuals, and training)
PE= Protective Equipment(such as nitrile gloves or eye protection)