Sensitometric comparison of speed group E and F dental radiographic films

Objective: To evaluate the sensitometric characteristics of Insight (R), (Eastman Kodak, Rochester, NY, USA) a new F-speed film, in fresh and depleted processing solutions and compare them with Ektaspeed Plus (R). Methods: Two sets each of Insight (IP) and Ektaspeed Plus (EP) films were exposed to radiation levels ranging from 10.7 to 685.2 mu Gy. One set of films was processed in fresh chemicals while the other set was processed in solutions that had been used for S days to process over 500 radiographs. Unexposed films of both types were processed in both solutions to determine base-plus-fog density, Speed and contrast were measured according to ISO definitions and at other levels of density. Results: IP was in speed group F as measured at optical density I above base-plus-fog when processed under both conditions. It was 25% faster than EP when both were processed in new solutions and 35% h faster in the old solutions, permitting a 20-24% reduction in exposure time. The speeds of both film types decreased when processed in used solutions, but the decrease was smaller for IP than for EP, Speeds at other density levels were greater for IP than EP. Contrast as defined by ISO, and over Other density ranges, was similar for both films. Conclusions: Insight is an F-speed film with a speed at least 25% greater than Ektaspeed Plus. 1P is more resistant than Ektaspeed Plus to decreases ill speed when processed in used chemicals. Contrast of IP and EP is comparable over several density ranges.