OBJECTIVES: To determine if a commercial device (Vischeck) for monitoring film processing quality was a practical option in general dental practice, and to assess processing quality among a group of GDPs in the West Midlands with this device. DESIGN: Clinical evaluation. SETTING: General dental practice, UK, 2004. METHOD: Ten GDP volunteers from a practice based research group processed Vischeck strips (a) when chemicals were changed, (b) one week later, and (c) immediately before the next change of chemicals. These were compared with strips processed under ideal conditions. Additionally, a series of duplicate radiographs were produced and processed together with Vischeck strips in progressively more dilute developer solutions to compare the change in radiograph quality assessed clinically with that derived from the Vischeck. RESULTS: The Vischeck strips suggested that at the time chosen for change of processing chemicals, eight dentists had been processing films well beyond the point indicated for replacement. Solutions were changed after a wide range of time periods and number of films processed. The calibration of the Vischeck strip correlated closely to a clinical assessment of acceptable film quality. CONCLUSIONS: Vischeck strips are a useful aid to monitoring processing quality in automatic developers in general dental practice. Most of this group of GDPs were using chemicals beyond the point at which diagnostic yield would be affected.