This list is neither complete nor comprehensive but a representative of the commonly occurring errors. If the dental surgeon can identify the causes of these errors and develop his own chart for troubleshooting, he will go a long way in giving his patient a quality controlled radiographic service. The dental student who makes radiographs at his graduate training frequently tends to make errors. This chapter intends to give him a basic framework on which to investigate these, and profit from the experience. Density is the amount of blackness seen in the radiograph. Contrast is the level of distinction that can be made between the layers of dark and light in the projection. Detail is the accurate reflection of the small anatomical minute in the film.