This test method covers the measurement of the ultraviolet absorption of a variety of petroleum products. It covers the absorbance of liquids or the absorptivity of liquids and solids, or both, at wavelengths in the region from 220 to 400 nm of the spectrum. The use of this test method implies that the conditions of measurement—wavelength, solvent (if any), sample path length, and sample concentration—are specified by reference to one of the examples of the application of this test method in the annexes or by a statement of other conditions of measurement. Examples of the application of this test method are the determination of the absorbance of white mineral oil, the absorptivity of refined petroleum wax, and the absorptivity of USP petrolatum. The values stated in SI units are to be regarded as the standard. The values stated in fahrenheit, feet, and inches, indicated in parentheses, are for information only.