What device and frequency are recommended for the developer temperature test?

• A. External handheld thermometer, weekly.
• B. Built-in thermometer in the processor, daily, within +/-0.5°F, as recommended by the manufacturer.
• C. Mercury thermometer, daily.
• D. Digital thermometer located outside the processor, daily.

Answer: (B)

Measuring the developer temperature is about ensuring the developing chemicals operate at the right conditions to produce consistent image density. The best approach is to use the processor’s built-in thermometer because it directly measures the temperature of the developer bath and provides an accurate reflection of the conditions affecting development. Checking this reading daily and keeping it within ±0.5°F, as recommended by the manufacturer, helps maintain consistent processing and quickly catch any drift that would affect film density. Using an external handheld thermometer or a thermometer located outside the processor can misrepresent the actual bath temperature, and mercury thermometers are not appropriate for routine QA.