The Basics of Paint Selection
Interior or exterior, choosing the right paint depends on a wide range of factors. But the most important is personal preference.

The Basics
The world of paint is divided into water-base and oil-base. Both types have four primary ingredients: pigment, solvent, binder, and additives. The ratio of these four ingredients is what distinguishes one paint from another.

Color
Pigment is color; it covers and hides the surface. All colors are born of the same base pigments: sienna, umber, titanium oxide, and zinc oxide. These pigments are ground into particles and stirred into paint. Since pigment is particulate, paint cans that sit for awhile need to be shaken as the color settles to the bottom.

Spreadability
Solvent is the industry term for spreading agent. Wax, water, and lime were once the dominant solvents used in paint. Nowadays water is the carrier for water-base paint, while petroleum serves as solvent for oil-base paints. The solvent may also be referred to as a medium, carrier or thinning agent. The other ingredients are suspended in this liquid base which thins the color mixture and allows it to spread evenly.

Adhesion
Paint is no good if it doesn't stick and maintain a uniform appearance. The binder joins the pigment particles, and gives paint its sticking power. It also dries into a protective finish. In water-based paints, the binder is usually a plastic, either acrylic, vinyl or a combination of both. The binder in oil-base paints is either a natural oil or a synthetic resin (alkyd). Paint is named for its binder, so latex paint is the common name for water base, while alkyd paint is the other name for oil base.

Oil vs. Water-Base
An oil-base coat takes longer to dry than latex, but some painters prefer it for this very reason. The longer the drying time, the better the paint will flatten out to hide brush marks. The odor is strong, but for durability oil base is hard to beat. Use it on primed walls or woodwork and already-painted surfaces. Cleanup is trickier than for water base, and must be done with mineral spirits or turpentine.

If they handed out a people's choice award for paints, however, water base would be the clear winner. It dries rapidly, so two coats can be applied in one day. Cleanup is done with soap and water. And, unlike petroleum-base paints, there is less odor when paint dries.

Gloss
Gloss, or finish, is determined by the ratio of pigment to binder. The more binder in a paint, the shinier the finish. Finish choices range from flat to high-gloss. Flat finishes are dull and hide imperfections. High gloss draws attention to itself, and imperfections, while giving off a brilliant shine. Low luster, eggshell, satin, soft gloss, and semi-gloss lie between the two extremes. Just as colors vary from brand to brand, so do finishes. When shopping for paint, ask to check the finish. Have the salesperson dab some paint on a mixing stick, then watch it dry.

Primer
Primer is like insurance: It seals any well-prepared surface, leaving a solid base ready for paint. Primers can be tinted and used to cover a darker shade. Primers can also hide slight imperfections in porous surfaces like new wallboard, patched drywall, wood, masonry, concrete or metal. Always check, though, to see that the primer is made for the surface you're covering.