As a result of a large test series performed over many years, the parameters for exposing various X-ray films with different X-ray units were described. As relatively new parameters the dose rate values of the X-ray units, the doses for the X-ray films and the contrast values between various densities were applied. In the future, if the manufacturers of X-ray units publish the dose rate results, we will have more exact imformation on the properties of the units. The dose values for the X-ray films are also important. This information enables the X-ray staff to calculate the exposure values and determine the radiographic contrast between unequal densities. This article aims at shedding more light on these parameters with the aid of a 300 kV halfwave unit and three X-ray films of different film classes. The values are presented in combination with X-ray exposure tables.