4.2.1 Process control tests and solution analysis. Test specimens shall be tested in accordance with table I and 4.2.1.1. In addition to the tests in table I, solution analysis shall be performed on all the processing solutions in the chemical conversion line (see 3.8) to verify that the chemical concentrations are within ranges established for optimum performance (see 6.11 and 6.14). Process control tests are conducted to determine compliance of the chemical conversion coatings with the requirements of this specification and are acceptable as evidence of the properties being obtained with the equipment and procedures employed.