Paints And Pigments Flashcards
What is the binding medium in oil paint?
The tiny particle of pigment are dispersed through the oil.
Solvents are used to dissolve the oil.
The solvent evaporates slowly and the binding medium dries forming a skin which sticks the pigment to the surface - it takes a long time to dry.
The oil reacts with oxygen in the air to form a tough, flexible skin.
Why do we use paint?
- For decoration to make things look bright and attractive
- For protection - to prevent wood from rotting and iron from rusting in rain. The oil based paints form a protective skin.
What is emulsion paint?
Emulsion paint is a water based paint that contains only a small amount of oil which is still the binding medium with pigment particles dispersed through it.
The oil is in the form of small droplets spread through the water to form an emulsion- droplets of one liquid within another that do not mix together.
The water evaporates and the oil droplets form a continuous film which sticks the pain to the surface.
What are colloids?
Colloids are mixtures of tiny particles of one thing in another.
Oil paint is a colloid because it is a mixture of solid particles in a liquid.
Emulsion paint is a colloid - solid particles dispersed in one liquid in another liquid.
What are thermochromic pigments?
Pigments which change colour with heat - can be used to show if an object is too hot to hold or is about to freeze
What are phosphorescent pigments?
Pigments that absorb and store day light energy and release it slowly and glow in the dark.
What are the 3 components of paint and what do they do?
Pigment- gives the paint it’s colour
Binding medium- sticks the pigment in the paint to the surface
Solvent- thins the paint so it is easier to spread.
