Painting is the favorite home improvement of the do-it-yourselfer. As remodeling contractors, we can tell you that many folks who otherwise hire others to do their work, choose to do their own painting.

We've had the opportunity to watch paint being made and, except for the huge size of the mixing vat, the whole process looks a lot like making cake batter.

It may surprise you to know it did us that water-based paint is nothing more than a mixture of water, rock, dirt and glue. The water is simply of the tap variety and the rock (usually titanium dioxide) is so finely crushed it looks like wheat flour. The dirt is nothing more than clay in the form of a very fine powder. And the glue is old fashioned white glue (polyvinyl acetate PVA). When the paint is used, the water evaporates and the glue holds the rock and dirt together, and to the wall.

The paint manufacturer uses other chemicals to stop bubbling, retard mildew, etc. But basically the toughest part of the process seems to be getting the paint from the vat into the cans.

The quality of the paint can be measured by the relative quantity of titanium dioxide to clay. More titanium dioxide and less clay equals better paint. Paint with too much clay has a tendency to chalk. Ask the salesperson at the paint store to tell you the percentage of titanium dioxide and clay. If he can't tell you or won't find out for you, don't buy his paint. Compare the percentages of different brands to help you make your selection. Be prepared to spend quite a bit more for good quality paint. Paying more for paint is, in the long run, less expensive than painting twice as often.

Besides cosmetics, painting provides protection against damage by moisture and the sun's rays. Paint is supposed to create a moisture barrier, not a vapor barrier. Your house needs to breath. Paint fails as a protector when moisture can't pass through it. It peels and splits when vapors can't penetrate it.

A few tips:

1. Pre-painting patchwork should be done with the proper putty or spackle. Use exterior latex putty for exterior nail holes and cracks. Always prime puttied areas. Putty absorbs paint differently than wood and will cause an uneven finish if left unprimed.

2. When patching with putty, wet the putty knife with water. The water acts as a lubricant and prevents the putty knife from dragging the patching compound out of the hole being patched.

3. Select the right paint brush. Natural bristles for oil-based paint and nylon or another synthetic for water-based paints.

4. Stretch a large rubber band across the top-center of the paint can. Remove excess paint by scraping the brush against the rubber band.

5. If you are using a roller, and the job looks like it's going to take an additional day, don't wash it. Simply wrap it in common household cellophane wrap and place it in the refrigerator overnight. It will be fresh for use the next day.