Things You'll Need
Instructions
Place the lamp on a stable, level surface. Position the x-ray film approximately 24 inches from the lamp. The film should be standing on its edge, facing the lamp, so light from the lamp shines through the film.
Measure the intensity of the incident light. This is the light that is shining on the film. Place the photometer in between the lamp and the film with the photometer's sensor directed towards the lamp (the photometer itself should be closer to the film). Read the value on the photometer and write it down.
Measure the intensity of the transmitted light. This is the light that is passing through the film. Place the photometer on the opposite side of the film, again with the sensor facing the lamp. Read the value displayed on the photometer and write it down.
Using the calculator, divide the value for the intensity of the incident light by the value for the intensity of the transmitted light. The log of this number is the radiographic density.