1.1 These reference radiographs illustrate various categories, types, and severity levels of discontinuities occurring in high-strength copper-base, nickel-copper, and related alloy castings. The reference radiograph films are an adjunct to this document and must be purchased separately from ASTM International, if needed (see 2.3). Categories and severity levels for each discontinuity type represented by these reference radiographs are described in 1.2. Note 1 -The basis of application for these reference radiographs requires a prior purchaser supplier agreement of radiographic examination attributes and classification criterion described in Sections 4, 7, 8, 9, and 10 of this standard. 1.2 These reference radiographs consist of forty-five 5 by 7-in. (127 by 178-mm) nominal size reproductions (twenty made from 1-in. (25.4-mm) plate castings exposed with low voltage X-rays for thicknesses up to and including 2 in.) and twenty-five made from 3-in. (76-mm) plate castings exposed with 2 MV X-rays or Cobalt 60 isotope for thicknesses greater than 2 in. up to and including 6 in. Unless otherwise specified in a purchaser supplier agreement (see 1.1), each discontinuity category is for comparison only with production radiographs produced with radiation energy levels within the thickness range covered by the category. These reference radiographs illustrate discontinuities in sand-cast manganese-nickel-aluminum bronze-alloy plates and are representative of those found in narrow freezing range (formerly "high shrinkage"), high-strength copper and nickel-copper alloys. Following is a list of discontinuity categories, types and severity levels for the adjunct reference radiographs of this standard (see Note 2):