Learning Event 4:
PERFORM DARKROOM INSPECTION PROCEDURES
Safety, cleanliness, heat, and humidity control are among the most important considerations in a
darkroom. Printing and processing operations in color photographic laboratories must contend with
dust, chemical fumes, humidity, and heat from processing solutions.
a. Dust can cause spots on final prints that will render the product unusable. Dust has ruined
more photographic projects than any other cause. Proper housekeeping, including periodic vacuuming
of equipment and furnishings, along with weekly wet mopping of the floors, are essential. No smoking
signs should be posted in all laboratories and finishing rooms. Smoke can coat negatives with a film that
causes imperfections on the print. Tobacco ashes can cause spots on the final print. Clean up all
chemical spills before they evaporate. Chemicals left to dry will leave a residue that can settle on
equipment causing damage. Change all filters in air conditioners and furnaces on a regular basis.
b. Humidity and heat must be controlled. Set air conditioners to maintain temperatures between
70 and 75 degrees Fahrenheit. Humidity should be maintained between 45 and 55 percent.
c. Chemical fumes can be held down or eliminated by circulating the air through high efficiency
filters that control airflow from one direction to the other at a uniform rate of flow. Inexpensive,
portable airflow units can be used in small darkrooms. Darkroom ventilation is essential to the safety
and comfort of personnel working in the laboratory.
d. Before using a laboratory it is necessary to observe all mechanical, electrical, and chemical
(1) Mechanical safety: Avoid loose clothing, such as neckties, unbuttoned lab coats, remove
wrist watches, and rings. Also, secure long hair. These items can become entangled in drives and other
moving parts of equipment in a laboratory. Print trimmers and scissors, used to cut film and paper, can
cut fingers if not used properly. When not in use, always put cutting tools away and lower and lock the
blade of a trimmer.
CAUTION: The blade of a trimmer must NEVER be left in the UP position.
(2) Electrical safety: Check power cords for worn or frayed insulation, loose connections and
broken parts to minimize accidents. Use circuit breakers or other approved means to prevent accidental
overloading. See that electrical equipment is properly grounded, and all power cords have polarized,
three-prong plugs attached.
CAUTION: Secure all electrical items such as timers, clocks, lamps, or any other
electrical item, near sinks, washers and other water or chemical containers.