The purpose of this part of ISO 11699 is to establish the performance of film systems. This part of ISO 11699 is applicable for the classification of film systems in combination with specified lead screens for industrial radiography (non-destructive testing). This part of ISO 11699 is intended to ensure that the image quality of radiographs — as far as this is influenced by the film system — is in conformity with the requirements of International Standards such as ISO 5579, ISO 17636 and EN 12681. This part of ISO 11699 does not apply to the classification of films used with fluorescent intensifying screens. The measurement of film systems in this part of ISO 11699 is restricted to a selected radiation quality to simplify the procedure. The properties of films will change with radiation energy, but not the ranking of film system quality. Additional methods for evaluating the photographic process are described in ISO 11699-2, by which the performance of film systems can be controlled under the conditions given in industry.