When you purchase paint, you do so sight unseen—and there is no way of knowing how good a paint is simply by examining the can. But Consumer Reports can help, with our tests of interior latex paint, kitchen-and-bathroom paint, deck treatments, and exterior paints and stains.

For interior latex paints, we judge "hiding power" (opacity), flow and leveling (how smooth paint looks when applied), and their resistance to staining, scrubbing, mildew growth, and sunlight. Our hiding chart (below right) consists of a 3x6-foot paper panel divided into three sections; each section contains six stripes ranging from pale gray to black. We paint the whole chart with a roller just like someone would paint a wall. The hiding power of a paint is determined by the darkest stripe that is not visible after the paint dries. We look at one- and two-coat hiding, and have found that some paints are as good when applied in one coat as others are in two.

Federal and state regulations limit the number of Volatile Organic Compounds (VOC's) that can be contained in paints. VOC's contribute to ozone and smog formation and are linked to respiratory illnesses and memory impairment. We list the claimed levels for each of the paints and run tests to make sure that the paints are meeting their claims. Recent tests uncovered paints with low levels of VOCs that were top performers.

We test the durability of exterior paints and stains outdoors. We evaluate and rate dirt accumulation, mildew growth, sun damage, and surface cracking. The paints and stains are applied to pine panels that are then exposed to the weather on special racks—one facing south and tilted to maximize exposure to the sun, rain, and snow and another facing north, upright, and under trees to maximize shade and dampness for mildew growth. Generally we find that paints are more durable than stains, and solid stains outlast semi-transparent stains, which in turn outperform clear sealers.