History of Pigments and Dyes

Natural Pigments and Dyes

• Organic Sources: Derived from insects, animals, or plants.
• Inorganic Sources: Derived from clays and minerals.

Differences Between Pigments and Dyes

• Pigments: Finely ground powders, insoluble in binders (vehicle).
• Dyes: Soluble liquids that permeate surfaces.
• Lake Pigments: Created by adding dyes to powdered minerals.

Historical Sources of Pigments

• Animal Sources:
  • Sepia from cuttlefish ink sac.
  • Red from cochineal (Mexico) and kermes (Near East).
• Mineral Sources:
  • Blue from lapis lazuli.
  • Green from malachite.

Binders Used

• Ancient Binders: Animal fat, honey (Egyptians), egg yolk & water (Italians).
• Modern Binders: Plant or synthetic gum, oil, egg white, latex.

Gouache vs. Watercolor

• Gouache: Opaque, water-soluble paint, lighter values added with white paint.
• Watercolor: Transparent, lighter values by diluting.
• Uses: Ancient Egyptian paintings, medieval illuminated manuscripts, 18th-century French and Italian artists.

Common Pigments and Dyes

• Iron Oxides: Red and yellow ochre, burnt sienna, umber.
• Plant Sources: Mata plant (red), indigo plant (blue).

Notable Historical Techniques and Uses

• Frescoes: Painting on wet plaster (buon fresco) or dry plaster (fresco secco).
  • Examples: Works by Giotto in the 14th century.
• Imperial Purple: Exclusive to Roman emperors, derived from murex snails.

Changes in Color Use

• Middle Ages: Luxury colors reserved for nobility; working class in drab colors.
• 14th Century: Introduction of brilliant black for the merchant class.

Plant Dye Mordants

• Function: Act as glue to hold dye to fabric, enhancing color.
• Common Mordants: Vinegar, urine, alum.

Evolution of Dyeing Techniques

• Indigo: Once banned in Europe for import; stabilized with mordants.
• Cochineal: Sourced from insects in Mexico, kept secret by Spanish.

Synthetic Dyes and Discoveries

• Prussian Blue: Discovered in 1704 accidently.
• Aniline Dyes: Derived from coal tar, drastically changed the industry.
• Perkin’s Mauve: Discovered in 1856, popularized synthetic purple.

Toxicity and Safety Concerns

• Toxic Pigments: Vermilion (mercury), Paris Green (arsenic), lead in paints.
• Health Effects: Rumored arsenic poisoning of Napoleon.

These notes cover the evolution of pigments and dyes from natural to synthetic, their historical significance, and their impact on art and commerce.