Study of Toluene Sulfur Dye
The use of substances as dye materials began thousands of years ago. We have accounts of Ancients who used dyeing materials for developing colors pleasing to the eye almost as early as the art of leaving written records itself. The point to note in this long period of time in the use of dyeing materials is the fact that it was always obtained until recent years from natural sources. Chemists interested in the formation of substances learned very little about the structure of dye stuffs until recent years- a fact that must be known before the systematic development of specific new dyes by synthesis can proceed very far.