What's in Your Paint
Whether you are looking at a 16th-century piece of artwork or the glistening shine of a newly coated car, there’s no question that there is more to paint than meets the eye. You can change the mood of a room or enhance the performance of a vehicle with a single coat of paint. How is this done? What exactly goes into paint that makes it so amazing? Most paints consist of the same basic components: pigments, binders, liquids, and additives. Each component serves a role in determining the quality of the paint as well as its performance both during and after application.
The pigment is a substance that imparts black or white or any colour to other materials especially a powdered substance that is mixed with a liquid in which it is relatively insoluble and used especially to impart colour to coating materials, such as paints and coatings, inks, plastics, and rubber. It looks a certain colour because it reflects wavelengths of light and absorbs others light. Traditionally, metal compounds or salts are used to create different colours so, for example, titanium dioxide, a bright white mineral often found in sand, is used to make white paint, iron oxide makes yellow, red, brown, or orange paint (think of how iron turns rusty red), and chromium oxide makes paint that's green. Black comes from particles of carbon. Different pigments are mixed together to make paint of any colour you can imagine.
Pigments are typically solids, so you could not use them to paint by themselves. They would be difficult to apply, they would not spread evenly, would not stick to paper or a wall, and would wash straight off if they got wet. That's why paints also contain substances called binders. Their job is to glue the pigment particles to one another, but also to make them stick to the surface you're painting. Some binders are made from natural oils such as linseed oil, but most are now made from synthetic plastics Visualize the binder as an invisible skin of plastic with a colourful pigment dispersed through it and you can see just how paint gives a layer of protection.
Mix a pigment and a binder and you get a thick gloopy substance that's difficult to spread. As its name suggests, a solvent is something that dissolves something else. The solvent's job is to make the pigment and binder into a thinner and less viscous (thick) liquid that will spread evenly. It’s why paint solvents are sometimes called thinners, which can be mineral spirits, turpentine and other substances. Water is now used primarily as a solvent for both interior and exterior architectural or decorative paint. Water is the best-known and most versatile solvent and it's widely used in water-based paints, including emulsions for walls, and watercolour paints for paintings. The majority, well over 90 per cent, of paint now used for architectural or decorative paint used in the home is latex or water-based paint. One big advantage of water-based paints is that they're relatively easy to clean up if you spill them and generally washes out of clothes. Other paints used mostly for exterior use or tougher jobs like furniture and metal use solvents made from strong organic, carbon-based chemicals extracted from petroleum.
Apart from the pigment, binder, and solvent, most paints also have additives of various kinds. For example, ceramic substances can be added to paints to improve their strength and durability. Fluorescent pigments added to paints make them glow in the dark. Additives in paint designed for outdoor use can help make things waterproof and rustproof, protecting against frost or sunlight, and keeping them free of mould and mildew. These additives are used in small quantities to impart additional qualities to the paint. These additives are used in the right proportion in paint to help improve the appearance, durability of coating and flow of paints