Pigments

Pigments are finely ground, insoluble solid particles that are used to impart color to other materials, such as paint, ink, plastic, fabric, and cosmetics. Unlike dyes, pigments do not dissolve in the medium but remain suspended in it. In paint and brush workflows, pigments are dispersed into paint and applied with brushes.

Description of what it is like

Pigments appear as fine, colored powders. The color intensity and coverage depend on the fineness of the grind and the purity of the material. They range from dull earth tones (ochres, umbers) to vibrant hues (ultramarine, vermilion).

Origin and where to find it

• Earth Pigments: Found in soil and clay (Ochres, Siennas, Umbers). Common in riverbanks or exposed cliffs.
• Mineral Pigments: Mined from specific rocks. Malachite (green), Azurite (blue), Cinnabar (red/vermilion), Lapis Lazuli (ultramarine).
• Organic Pigments: Charred wood or bone (Carbon Black, Bone Black), or plant lakes (though lakes are dyes attached to a pigment base).
• Synthetic Pigments: Created through chemical reactions (e.g., Prussian Blue, Lead White).

Minimum processing required

1. Collection: Mining the mineral or collecting the organic source.
2. Grinding: Using a mortar and pestle or mill to crush the material into a fine powder. Coarse particles make gritty paint.
3. Washing (Levigation): Mixing the powder with water to separate heavy impurities (which sink) from fine pigment particles (which stay suspended longer), then decanting.
4. Drying: Removing moisture from the refined pigment paste.

Tools needed to work on it

• Mortar and Pestle: For initial crushing and grinding.
• Grinding Slab and Muller: A flat stone and a heavy, flat-bottomed stone to grind the pigment into a very fine paste with water.
• Bowls/Jars: For washing and settling.
• Sieves: To remove large debris.

Mixing pigments for paints and brushes

• Wetting: Mix pigment with a few drops of water or solvent to break clumps and reduce dust.
• Binder dispersion: Mull into the binder until each particle is coated to improve coverage and stability.
• Pigment load: Increase for opacity or reduce for transparency while avoiding an overly brittle paint film.
• Brush consistency: Thin gradually until the flow is smooth without dripping or grit.
• Stroke test: Test on a palette or paper to confirm color, transparency, and brush mark before applying.

Common forms of use

• Dry Powder: Stored for later use.
• Paste: Mixed with water or oil for immediate paint making.
• Cakes: Pressed pigment (sometimes with a little binder) for storage.

Possible substitutes

• Textile Dye: Soluble colorants derived from plants (berries, roots). They are often less lightfast and less opaque than pigments.
• Colored Clays: Can be used directly as crude pigment.
• Ash/Charcoal: Readily available substitute for black pigment.

Limitations and common failures

• Fading (Fugitive Colors): Some pigments lose color when exposed to sunlight (UV).
• Toxicity: Many historical pigments are toxic (Lead White, Cinnabar/Mercury, Orpiment/Arsenic).
• Incompatibility: Some pigments react chemically with certain binders or other pigments (e.g., copper pigments can spoil in oil).

Risks and safety

• Inhalation: Breathing fine dust is dangerous (Silicosis, heavy metal poisoning). Always wear a mask or grind wet.
• Toxicity: Handle minerals like Malachite, Cinnabar, and Lead with extreme care. Wash hands thoroughly.

Related materials

• Paint: The primary application of pigments (Pigment + Binder).
• Verdigris: A common copper-based green pigment.
• White Lead: A common lead-based white pigment.
• Ink: Pigments suspended in a liquid for writing.
• Glue: Can act as a binder.
• Clay: A source of earth pigments (Ochre).