Abstract: The basic requirement for the equality is the equal contrast and unsharpness of the testing image between a digital radiological technical classification and a film radiological technical classification on the basic theory of radiography. The procedure for the equality evaluation consists of the analysis on product, determining essential performance of the detetor system, inspection test with the digital radiographic system and deciding the equality. An example was given which showed the practical evaluation procedures for the substitution of the technical classification of digital radiography for the technical classification of film radiography.