C1:Pigments Flashcards
What is a pigment?
A pigment is a colored substance used in paints or dyes.
What are pigments derived from?
plants, rocks,animals or from synthetic sources.
What are the ingredients in paint?
Pigment-the substance that gives the paint its colour.
binding medium- sticks the pigments to the surface being painted
solvent- thins the paint so it spreads more easily.
What are the two types of paint?
Emulsion paints- water based
Oil paints- oil based
What happens to emulsion paint when left to dry?
As the water evaporates, the paint dries and the other ingredients join together to form a tough, coloured layer on the painted surface.
What happens to Oil paint when left to dry?
The solvent in oil paints is a hydrocarbon oil. This evaporates as the paint dries AND oxygen in the air oxidises the hydrocarbon molecules. This forms a very tough layer on the painted surface.
What is a colloid
A colloid is a type of mixture in which one substance is spread or dispersed evenly in another substance.Colloids are different from solutions because none of the substances are dissolved. The solvents they contain are there to spread the paint thinly rather than to dissolve it.
How are the substances dispersed evenly in a Colloid?
The components of a colloid do not separate out or settle the the bottom. This is because the particles are dispersed throughout the mixture and are too small to settle.
