There are two main types of paint, water-based and oil-based. Those terms refer to the material that is used as a solvent in the paint, meaning the liquid part that evaporates, leaving the color on the walls. Besides the type of paint you choose, there are also different finishes for interior painting, such as eggshell, flat, or semi-gloss. Here we'll look at some of the positives and negatives of each type of paint and which kind of finish may be the right one for your particular project.
There are some interior painting projects that are better suited for water-based paints and some that work better with oil-based. A positive quality of water-based paints is their lack of that tell-tale paint smell. Because the solvent is water, there isn't the strong chemical odor of oil-based paint. Water-based paint cleans up with soap and water, where oil-based paints require that you use paint thinner or turpentine to clean up. Something that can be both a positive and a negative is that water-based paints are fairly quick-drying, which sometimes leads to more brush lines, as the paint dries to fast to smooth them out. It may require an extra coat or two. Oil-based paints, though not the most eco-friendly, are popular for their smooth finish. However, besides the environmental issues, this type of paint has some other disadvantages. Oil-based paints have a drying time of at least 24 hours. If you don't wait until the first coat is dry, you could have disastrous results. Also, it is usually quite a bit thicker than water-based, and care should be taken not too use too much or the paint may puddle while drying. Oil-based is a good option for trim and doors, water-based is an environmentally friendlier option and works well on walls and ceilings. It can also be used for trim work, but more coats may be required.
Once you've decided what type of paint to use (water or oil-based, latex or acrylic), you next have to choose a finish. The finish refers to the look and feel of the paint when it dries. Popular finishes are flat, semi-gloss and high gloss, though there are many more finishes and each paint manufacturer may provide different options. Flat finishes are good on walls, where a high gloss finish might be a little much. Semi-gloss could work, too, if you want a little bit of shine. High gloss paints are the easiest finish to clean and work best for heavier used areas, like bathrooms and kitchens and for things like trim and doors. It is really up to you which finish to choose. Remember that it's always a good idea to paint a sample section on the wall and live with it for a day or two to see if that is indeed the right color for your room.