Radiography produces an image, a radiograph, using x-rays. X-rays penetrate solid objects and provide a detailed view of the internal structure. The image produced is a shadow image since the x-rays pass through some parts of the solid object easily and some parts less easily. Differences in density, material thickness, attenuation characteristics, and material composition result in the shadow image. Flaws, voids, inclusions, cracks, etc., are variations that can be identified. Constellation has the two methods of radiographic evaluation, film and real-time.