Volume solid

Volume solid is the volume of paint after it has dried. Paint contains solvent, resin, pigments and additives. After applying the paint, the solid portion will be left on the substrate. Volume solid is the term which indicates the proportion of the solid contacting the paint on a volume basis. For example, if paint is applied in a wet film at a 100 μm thickness, and the volume solid of paint is 50%, then the dry film thickness will be 50 μm as 50% of the wet paint has evaporated. Suppose the volume solid is 100%, and the wet film thickness is also 100 μm. Then after complete drying of the paint, the DFT will be 100 μm because no solvent will be evaporated.
This is an important concept when using paint industrially to calculate the cost of painting. It can be said that it is the real volume of paint.
Here is the formula by which one can calculate the volume solid of paint,
A simple method that anyone can do to determine volume solids empirically is to apply paint to a steel surface with an application knife and measure the wet film thickness. Then cure the paint and measure the dry film thickness. The percentage of dry to wet is representative of the percentage of volume solids.
In earlier days, the volume solid was measured by a disc method but now a sophisticated instrument is also available which takes only a drop of paint to check the volume solid.
Understanding 'volume solids' allows you to know the true cost of different coatings and to know how much paint is being used to perform its function. Generally, more expensive paints have a higher volume of solids and therefore provide better coverage.