Don't trust the final product will look like the small paint swatch card you saw in the store ... it won't! There are many factors that change between when you look at that tiny swatch and then see your room fully washed in the same color. Lighting, paint sheen, wall texture — all play tricks on the eye and can alter the original color dramatically. To ensure you like the paint color(s) you're thinking about, test the color on a sample board first. Buy a quart of the color in question (some suppliers even offer smaller sample jars) and paint them on a 3-foot x 3-foot square of scrap wood (make sure you prime it as you would the walls you'll be painting). Next, place the board in the room and look at it at different times of day as the lighting changes. This sample board — and not the tiny paint swatch card — will give you a much better idea of the true effect the color will have in the room.