In the reported test program, a number of commercial dielectric paper grades were analyzed for electrical and physical properties, such as basis weight, dielectric coating weight, solvent holdout, charge acceptance and decay, surface and volume resistivity, caliper, and gloss. Chemical compositions of the dielectric and backside coatings were also determined. Cross-sectional photomicrographs of the paper samples were taken under an optical microscope to examine the construction of each grade. The analytical and photographic work showed wide variations in the makeup of prominent commercial dielectric papers.