Gary Nannini knew he was in trouble when a home designer in California told him to build a “white” pool.

“Everything in the home was white — carpets, walls, furniture — so everything we did was white,” says the owner of Pool Art by Gary Nannini in Brentwood, Tenn. “We mixed some white portland [cement] and white sand for decking. We did a white tile wall, white plaster, white brick.

“There wasn’t much room for landscaping to calm it down, so when we were done and you looked out there on a sunny day, it was blinding,” he adds.

Color can excite the senses just as easily as it can create chaos and disruption. The human brain currently registers an estimated 2.3 million colors, according to Science News.

Color vision, however, may have evolved as a survival skill. In the 19th century, biologists believed that red-green perception developed 23 million years earlier to help women, the traditional “gatherers” of the family unit, distinguish between a ripe fruit and the foliage surrounding it. Researchers now say that such perception also helped attract humans to plants and fruits with the highest nutritional content.

Today, those underlying principles of contrast and attraction can be put to work in a backyard. The theory behind it begins with the color wheel, a spectrum of 12 hues first refracted by Sir Isaac Newton in 1666, which can be mixed and matched to create a palette. A color has the capacity to change in three ways — hue (getting redder, bluer, greener or yellower), value (light vs. dark) or chroma (bolder vs. grayer). (For more on color terms, see Learn the Lingo.)

These tenets, however, are complicated by swimming pools and spas. “Colors change around water,” Nannini says. “Designers need to not only grasp the basic theory of color, but also how light and water react to it.”

The following five guidelines explain the theory behind incorporating color in a backyard. Used with care, they can help you make bold, yet harmonious, outdoor design statements.

1 Ease your clients into a color comfort zone.

Though you may understand how color works, your clients probably won’t. Show them magazines, pool design books and photos of your projects to get a feel for their preferences.

“I ask clients to take a word association quiz about color swatches,” says Leatrice Eiseman, director of the Eiseman Center for Color Information & Training in Bainbridge Island, Wash. “I show them a swatch of color and ask them to write down the first thing that comes to mind.

“For instance, if you show someone a pale pink stone, and they write down ‘Aunt Gertrude’s sweater,’ you may find out that Aunt Gertrude is their favorite person in the world,” she adds. “You get clues about what colors mean to a client.”

It’s also important to learn how to take client feedback and turn it into design language. If the person complains that a design looks “boring,” he or she may want more color contrast. Or if the client says a pool is “messy,” you may need to start removing elements and reducing color. (For more on how color evokes emotions, read In Living Color.)

2 Consider the site’s limits — and possibilities.

In many cases, the site dictates the use of color. Whether the property is on a waterfront, at the base of a mountain or in a flat suburban development, the colors in the pool and backyard need to complement the environment.

“The greatest problem I see is when people don’t pay attention to the context. They try to choose their colors in a vacuum,” says Sandra Austin, a landscape designer in Burke, Va., and author of Color in Garden Design (The Taunton Press, 1998).

“Your local color would be perceived as timeless and appropriate,” she says. “Harmony has a specific meaning in design, and it means the colors proceed to each other in regular, equal steps within the yard and beyond.”

Chad Robert agrees. “A lot of people only think of the property line as their site boundaries, and that’s not right,” says the principal/owner of Exteriors by Chad Robert Inc. in Phoenix. “Your site boundaries visually extend beyond property walls, and you need to take that into consideration.”

One of Robert’s current projects, for instance, features incredible views of Arizona’s Camelback Mountain. “I’m pulling back in terms of my color use because I don’t want to distract your eye. So there are times when you want to use restraint, and there are times when you want to be a little more dramatic,” he says.

3 Create contrast.

Contrast makes colors appear more vivid, which draws focus away from a property’s unattractive areas. Without it, a backyard will look “blah.” The most dramatic contrast is created by complementary colors — those on opposite ends of the color wheel.

Michael Giordano saw this happen with a pool he built two years ago. “We don’t recommend monochromatic schemes, but we did this pool in all gray tones because that’s what the client wanted,” says the partner at Artisan Pools in Pine Brook, N.J. “We took a few photos from a distance, and you couldn’t tell the difference between the patio, coping or pool.

“It all blended together,” he notes. “That’s why we like to vary the tone.”

Contrast also can be created by varying light and dark colors in the same family, or by using multiple textures of materials. Neutral colors can be implemented to tone down bold contrasts or allow transitions between hues.

Keep in mind that too much contrast in a small space will appear garish. “There are certain bright colors you don’t want to put right next to the pool,” says Mike Exstrom, general manager of the Thousand Oaks branch of California Pools & Spas, a Pool & Spa News Top Builder. “Bold colors are usually found around waterfeatures.

“If you have a cascade or a dramatic spa, that’s the place to put them,” he adds. “Most of the time, it’s used as an accent.”

Avoid bright colors in small spaces; instead, opt for natural-toned hues. For long distances, place a colored wall or bright flowering plant at one end to draw the viewer’s gaze inward. Whites and pale pinks, blues and yellows can brighten shaded areas, giving lot corners much-needed perspective.

“Use bold color schemes on vertical surfaces, meaning raised and facing eye-level surfaces,” says Ben Dozier, owner of Root Design Company in Austin, Texas. “We use neutral colors on horizontal surfaces, the ones that you walk on. That’s practical since bold decking is too hot to walk on in the summer.”

4 Adjust for lighting.

Natural and artificial lighting will change the way color is perceived. In sunny areas, most colors are washed out: White becomes blinding and pale colors fade. On the other hand, intense sunlight will make bright reds and blues pop.

“Sun has a tendency to rob color,” Eiseman says. “So if you were planting marigolds near a body of water, they’re not going to reflect quite as yellow if it wasn’t so bright.”

At night, the opposite occurs. White flowers and pastel stones gain an ethereal quality. In such low-light conditions, light-dark contrasts show up well. For example, a softly lit blue pool with dark green foliage and pale flowers will be stunning at dusk.

Artificial lighting has its own effect. Fluorescent lights illuminate differently than incandescent. “Different lights have different color intensities,” says Raymond Jungles, principal landscape architect at Raymond Jungles Inc. in Miami. “Metal halide is white, mercury vapor is blue and sodium vapor is orange.”

In most cases, landscape designer Robert specifies that his plants be lit with an ice blue halogen lens, which mimics natural light. He uses incandescent lighting only to illuminate focal points such as statues and fiberoptics inside the pool, not along the perimeter.

5 Use straightforward strategies.

In most poolscapes, color can be incorporated via waterline tiles, finishes, hardscaping or plant material. If you’ve never experimented with color, start in areas of the backyard that can be easily changed.

“Colors can be scary sometimes for people, especially when you get into bright ones,” Robert says. “I think it’s good to take risks, but you want to do it in a way that can be changed, if needed.”

Focus on walls that can be repainted or in easy-to-remove elements such as pots, bowls, garden art or small shrubs. “Plants are a good area to start,” says Dean Hill, ASLA, co-host of “Grounds for Improvement,” a landscaping show on the DIY Network. “The natural colors are an excellent starting point for your material elements because hardscaping should probably be those subtle, natural tones.”

Some landscapers suggest selecting three colors, three plant varieties and three textures. Mix and match within those nine elements without using more than five at any given time.

“If your eyes take in something that is disharmonious [or] jarring, you feel it as an emotion,” landscape architect Jungles says. “To me, harmony is a tranquil feeling when everything is in balance and nothing is out of place.”