The darkroom lighting should be properly illuminated with what wattage range for the bulb?

• A. Dim with a 100W bulb
• B. Red-light only with a 5W bulb
• C. Brightly lit with a 60W bulb
• D. Properly illuminated with a 7.5 to 15 watt bulb

Answer: (D)

Safelight intensity in the darkroom is the key idea. Radiographic films are sensitive to light, so you use a red safelight that provides enough visibility to work without exposing or fogging the film. The standard guideline is a bulb in the 7.5 to 15 watt range. Within this range, you can see well enough to handle supplies and process films safely, while avoiding fogging that would occur with brighter lights. A higher-wattage bulb would be too bright and risk fogging, whereas a wattage at or below 5W would be dim and hinder safe, efficient work. Therefore, the proper choice is a bulb within 7.5 to 15 watts.