Radiographic interpretation is a complex art involving visual discriminations of subtle radiographic details. The unambiguous communication of these details between purchaser and supplier has frequently proven a difficult task. Reference radiographs supply a direct visual reference to a range of discontinuity types and severity levels, providing a visually communicated basis for evaluating components to an agreed upon acceptance level. The first set of widely used reference radiographs were assembled by the U.S. Bureau of Engineering in 1938. This set of production radiographs illustrated a variety of defect types in steel castings and wasadopted by ASTM in 1952 following the formation of Subcommittee E7.02 on Reference Radiographs. ASTM currently maintains 13 reference radiograph documents covering castings of a wide variety of materials and steel weldments. All current documents are produced using made-to-purpose hardware containing intentionally produced discontinuities of various types and severities. The future holds a great number of challenges for this activity due primarily to two factors. First is the rapid development of many new materials for aerospace and other applications. These materials include composites, ceramics, and exotic alloys. Second is the development and use of advanced radioscopic imaging systems in which radiologic interpretation is performed using video displays rather than the traditional film viewers. The development of reference radiological images appropriate to these systems offers many new challenges.