The method used to dissolve and handle granules of pigments in a painting, in conservation terminology it is called a binding agent, which along with pigments, can be identified using microchemical reagents. 

There are techniques used for identifying colors (drop test) and techniques used for the identification of organic binders (selective coloring). 

The identification of pigments in paint layers is achieved by applying the appropriate reagent onto the sample. The reagent selected needs to have the appropriate properties to react to a specific dye medium, so that a detectable visible change can occur.

For the detection of binding agents invisible under an optical microscope, the properties of certain chemical substances are applied to the binders of the paint, a process which colors them and makes them  visible under an optical microscope.