5.1 Density is weight per unit volume. It is a key property in the identification, characterization, and quality control of a wide range of materials. Density measurements in terms of weight per gallon are commonly used to check paint quality. If the density is not within specification, there is a good chance that there was a mischarge or other serious problem.

5.2 This test method is suitable for the determination of density of paint and related products and components when in liquid form. It is particularly applicable when the fluid has too high a viscosity or when a component is too volatile for a density balance determination.

5.3 This test method provides for the maximum accuracy required for hiding power determinations. It is equally suitable for work in which less accuracy is required, by ignoring the directions for recalibration and consideration of temperature differentials, and using as the container a "weight-per-gallon" cup.

5.4 Automatic equipment for measuring density is available (see Test Method D4052) from several manufacturers. Such apparatus has been used for resins and latices as well as for oils and solvents. Before such equipment is used for a given product, results must be checked very carefully. Particularly with paints, inks, and resins, there are possibilities of gumming, fouling, and other interferences with operation.