Paints and Pigments

Paints and Pigments

1. Pigments give paints their colours

   • Paint usually contains the following bits: solvent, binding medium and pigment
   • The binding medium is a liquid that carries the pigment bits and holds them together. When the binding medium goes solid it sticks the pigments to the surface you've painted
   • The solvent thins the paint and makes it easier to spread

2. Paints are Colloids

   • A colloid consists of really small particles of one kind dispersed in another kind. They're mixed in, NOT dissolved
   • The particles can be bits of solid, droplets of liquid or bubbles of gas
   • Colloids don't seperate out because the particles are so small. They DON'T settle out at the bottom.
   • A paint is a colloid where particles of a pigment (usually a solid) are dipersed through a liquid.

3. Some paints are Wtaer-based and Some are Oil-based

   • Emulsion Paints
     • Emulsion paints are water-based. the solvent used in these paints is water, and the binding medium is usually an acrylic or vinyl acetate polymer.
     • A water-based emulsion dries when the solvent evaporates, leaving behind the binder and pigment as a thin solid film. A think layer of emulsion paint dries quite quickly.
     • Emulsion paints are fast-drying and don't produce harmful fumes- so the're ideal for painting things like inside walls.
   • Gloss Paints
     • Traditional gloss paint and artists' oil paints are oil-based. This time, the bimding material is oilm and the solvent is an organic compound that'll dissolve oil.
     • Oil paints dry in two stages. First the solvent evaporates, and then the oil is oxidised by oxygen in the aur before it turns solid. they take longer to dry than emulsions.
     • Oil paints are glossy, waterproof and hard-wearing, but the solvents used to make them often produce harmful fumes. They're nest used for painting things like outside doors and metalwork.