A Comparison of Five Methods for Monitoring the Precision of Automated X-Ray Film Processors

Five different methods for preparing sensitometric strips used to monitor the precision of automated film processors are compared. A method for determining the sensitivity of each system to processor variations is presented; the observed statistical variability is multiplied by the system response to temperature or chemical changes. Pre-exposed sensitometric strips required the use of accurate densitometers and stringent control limits to be effective. X-ray exposed sensitometric strips demonstrated large variations in the x-ray output (2 σ ≃ 8.0%) over a period of one month. Some light sensitometers were capable of detecting ± 1.0 °F (±0.6 °C) variations in developer temperature in the processor and/or about 10.0 ml of chemical contamination in the processor. Nevertheless, even the light sensitometers were susceptible to problems, e.g., film emulsion selection, line voltage variations, and latent image fading. Advantages and disadvantages of the various sensitometric methods are discussed.