Most of us open a can of paint, stir it and start rolling. We don’t think much about what’s inside. But knowing the basics helps you understand why one paint covers well, another wipes clean, and another peels.
Here’s a plain, general look at how paint is made. I’m a painter, not a chemist, so I’ll keep it to the basics.
The four main parts
Almost every paint is built from the same four groups of ingredients: pigment, binder, liquid and additives.
Pigment
Pigment gives paint its color and its hiding power. White paint relies heavily on a white pigment that scatters light and covers what’s underneath. Color comes from other pigments, which can be mineral or made in a lab. Pigment is ground into very fine particles so it spreads evenly instead of looking gritty or streaky.
Some paints also contain fillers, sometimes called extenders. These add body and affect how the paint feels and dries.
Binder
The binder is the glue. It holds the pigment together and makes it stick to the wall. When paint dries, the binder forms the film you see and touch. In most house paints today, the binder is acrylic. Others use alkyd, which is oil-based, or other resins. The type of binder has a big effect on how flexible, tough and washable the dried paint is.
This is why two paints that look the same in the can can behave very differently on a wall. The binder does a lot of the work.
The liquid
The liquid carries everything and makes paint workable. In water-based paint, the liquid is water. In oil-based paint, it’s a solvent. Once paint is on the wall, the liquid leaves. It evaporates, and what remains is pigment held in binder. That’s the paint film.
This is also why a freshly painted room can smell. Some of what evaporates is volatile organic compounds, often called VOCs. Many paints today are made with low amounts, and ventilation helps in any room being painted.
Additives
Additives are small amounts of ingredients that fix specific problems. They can help paint flow and level, keep it from foaming in the can, keep pigment mixed, help it resist mildew on the wall, or change how thick it is. You usually can’t see them, but they matter.
From factory to your wall
In a factory, pigments are mixed into some of the liquid and ground at high speed until the particles are fine and evenly spread. Then the binder, more liquid and the additives are blended in. The batch is checked for things like thickness and consistency before it’s put in cans.
If you buy a color, it often gets finished at the store. A base paint goes in the can, and colorant is added by machine to match your color. The can is then shaken so it’s thoroughly mixed.
Why this matters for your job
- Better paints usually have more of the good ingredients. More quality pigment and binder generally means better coverage and a tougher film. Thin, cheap paint can mean extra coats.
- Exterior paint is built differently. It’s made to flex with temperature and handle sun and moisture. Interior paint is built to be scrubbed and to keep a clean look.
- Stir your paint. Pigment settles. A good stir, or a shake at the store, puts it back together.
- Mix cans for large areas. Batches and tint can vary slightly, so painters often blend cans together so the color stays consistent across a wall.
What I’d do with this
You don’t need to be a chemist to pick good paint. Just know that the can’s label matters, and so does the prep under it. For help choosing a paint for your home, call me at (858) 333-2396 for a free estimate, or use the contact page. You can also read about our services.
FAQ
What are the main ingredients in paint?
Paint is made from pigment for color and coverage, a binder that holds it together and sticks it to the surface, a liquid that makes it workable, and small amounts of additives. When the liquid evaporates, the pigment and binder are left behind as the dried paint film.
What is the difference between water-based and oil-based paint?
The difference is the liquid that carries the paint. Water-based paint uses water and cleans up with it. Oil-based paint uses a solvent, which has a stronger smell and slower drying. Today, most house paint is water-based acrylic, though oil-based products are still used for certain jobs.
Why does paint smell, and does it go away?
Some of the liquid leaves the paint as it dries and gives off a smell, including VOCs. The smell fades as the paint dries and cures. Open windows and run fans while painting. Low-odor paints are available if you’re sensitive.