Organic pigments are traditionally transparent. However, modern manufacturing techniques are capable of imparting properties not previously associated with the chemical type: it is now possible to produce high opacity organic pigments.
Organic pigments are relatively new. Although, natural dyes have been precipitated on to inorganic bases (known as lakes) and used in artists’ colors since the Middle Ages (e.g. madder lake and crimson lake), true organic pigments have only been known since the early years of the twentieth century.
Most organic pigments show better transparency as dispersion improves, while in the case of the larger particle size inorganic pigments, opacity is improved by good dispersion.
