Optical density changes in dry-processed films.

Dry-processed radiographic films should be stored in a temperature-controlled environment away from direct light to prevent image deterioration. However, films occasionally are subjected to other conditions, such as when they are left inadvertently on viewing boxes or removed from the radiology department.To assess the effects of heat and light on optical density in radiographic films produced with dry laser imagers.Step-wedge images generated by a dry laser imaging system were placed on an illuminated viewing box, inside the trunk of a car and in direct sunlight on a hot day for varying lengths of time. Changes in optical density (OD) then were measured with a densitometer. Changes of more than 2 standard deviations from the original OD were attributed to the effects of light and heat.The films left on a viewing box and inside a car's trunk did not show significant changes in OD. However, films subjected to direct sunlight for 30 minutes or more at an average temperature of 40 degrees C (104 degrees F) showed significant changes in OD in the straight-line portion of the Hurter and Driffield curve.Dry-processed films can degrade when exposed to temperatures higher than 35 degrees C (95 degrees F) and should be stored properly to avoid affecting their diagnostic quality.