A system for determining image intensity of a radiograph includes an illuminator for providing lighting to the radiograph, an image reference standard having a predetermined color, a digital imaging device for obtaining a digital image of the radiograph and the image reference standard, a computer for receiving and storing the digital image and for executing programs, and an image analysis program being executed on the computer for providing a first image intensity value of a target area in the radiograph and a second image intensity value of the image reference standard and for computing a normalized image intensity value of the target area using the first and second image intensity values. In one embodiment, the image reference standard is an image reference standard of a black color or a white color.