What type of dye are synthetic dyes commonly known as?

Synthetic dyes are commonly referred to as coal tar dyes because they originated from coal tar, a byproduct of the carbonization of coal that is rich in aromatic compounds. These dyes were initially developed in the 19th century and are characterized by their vibrant colors and ability to bind to various types of tissue. In histopathology, coal tar dyes are particularly valuable due to their effectiveness and specificity in staining biological tissues, which assists in the identification and analysis of different cell types and structures.

The term "coal tar dyes" is significant in this context because it highlights the synthetic nature of these dyes, differentiating them from natural dyes derived from plant or animal sources. Understanding this classification is critical for histopathologists when selecting the appropriate staining techniques for their specimens.