The wrong colors can make an automaker bluer than blue.

But the right ones can make an automaker see green.

A car can have the smoothest engine, the best brakes and the nicest interior, but if it’s the wrong color, it just won’t sell, said Alan Starling, a Kissimmee, Fla., auto dealer who owns Pontiac, Buick, Chevrolet, GMC and Oldsmobile dealerships.

After the engineering is done, it all comes down to choosing the colors that work best with the shape and style of the car.

But unlike many other aspects of automaking, there is no exact science for this. Automakers say color selection involves studying trends, monitoring the mood of the country, gut feelings and, sometimes, even luck.

Take the case of the Pontiac Bonneville sports sedan.

One day about three years ago as Pontiac engineers were putting the final touches on the new Bonneville, the time came for Pontiac Division General Manager John Middlebrook to choose which exclusive colors would make it to production.

Since the Bonneville would be built in a General Motors factory along with several other brands of GM cars, many of the colors were to be shared between Buicks, Chevrolets, Oldsmobiles and other GM vehicles.

But every year, Middlebrook said, each division chooses two or three exclusive colors.

Two other GM divisions didn’t want a dark green that was available that year, but Middlebrook had a hunch that it might work on the Bonneville. So he had one painted in that color.

“When I looked at the Bonneville, I saw a lot of Jaguar influences in the rear haunches in that product. I thought British Racing Green was the right color. It just looked like the right thing to do,” said Middlebrook from Pontiac’s headquarters in Michigan.

Middlebrook liked what he saw and made the dark green an exclusive Pontiac color. It was a decision that has led Pontiac to a pot of gold at the end of a long rainbow of sales.

The Bonneville has become one of the hottest selling Pontiac sedans in years, and the dark green version has been leading the way.

Middlebrook said customers order about a third of all Bonnevilles in dark green. On the more expensive SSE and supercharged Bonneville SSEi models, dark green accounts for 40 percent of sales. But it’s rare, Middlebrook said, for one color to dominate so.

“We used a gut judgment on that dark green, but as it turned out, it really did fit the product and image,” said Middlebrook.

Orlando businessman Bob Kearney agrees. When he decided to buy a new Bonneville recently, picking the color was the easy part.

He grew fond of British Racing Green Jaguars when he and his wife lived in Great Britain.

And because the Bonneville also reminded him of the Jaguar, he said he never considered any color other than dark green.

“It was the first impression we had of Jags. It conveyed a certain elegance to most people,” said Kearney, of Kearney Systems in Orlando.

Kearney said his Bonneville, an SSE model outfitted with gold wheels and gold pinstripes, draws plenty of compliments.

“It turns heads and is constantly getting second looks,” he said.

But some cars and colors don’t work out so well.

Toyota has found that a shade of purple on its midsize Lexus ES 300 luxury sedan has underwhelmed buyers.

Don Brown, Toyota’s national product manager, said Toyota monitors how well colors sell two ways.

“We track the volume we sell and the velocity _ the average number of days a car sits in stock before it is sold. We might be selling an acceptable volume of purple cars but if they sit at the dealership three times longer, we might discontinue that color or change it,” Brown said from Toyota’s U.S. headquarters in Torrance, Calif.

At Toyota, choosing colors is a complex procedure because the automaker’s vehicles are exported all over the world. And car buyers in each country have unique tastes, Brown said. Not only that, but in the United States there are regional color preferences. For example, lighter colors, he said, are generally more popular in the Southeast.

Many colors that are popular in Japan and other countries won’t sell here, Brown said. In Japan, shades of yellow and gold are popular on cars because, he said, Japanese tea often has those colors and car buyers there are familiar with them.

In Europe, dull shades of green and some shades of yellow are popular on Range Rover luxury sport-utility vehicles, but those colors wouldn’t sell well here, said Bill Baker of Land Rover of North America, the Maryland-based importer of the British-made vehicles.
“Color is a matter of style. Like a suit of clothes, it’s an expression of your personality,” said Baker.

Automakers such as Land Rover and Toyota that export vehicles all over the world have a tougher time choosing the right colors.

“If every country wanted 10 exclusive colors, we couldn’t do it” because the production lines are not designed to handle that many different color combinations, he said.

Even though automakers know that buyers always will want basic colors such as white, red, blue and black, there still is a lot of testing, analyzing, predicting and guesswork involved in picking other colors.

“A lot of it is gut feeling, trying to match the color and shape of a car. Like any other process, we try to study our market and study where trends are going,” said Brown of Toyota.

He said Toyota designers try out colors on clay mockups of cars, sometimes using more than one color at a time. One side of a car could be green, while the other side might be red, he said.

At General Motors, designers use a special kind of paint that can be peeled off.

Pontiac’s Middlebrook said that no longer are color decisions made based on what looks good on a 10-inch color card. Now, all colors being considered are applied to the cars.

“It is very important that you go beyond looking at color chips. You can only really make a decision by putting the color on a car. We put the peel coat on and take the car outside. We look at every new color on the product before we make a decision. And we find that what might look beautiful on a 10-by-10-inch patch might change once it’s outside on the car with all the trim in place,” he said.

In the old days, GM used to paint thousands of cars different colors, Middlebrook said.

“Not many years ago, we had a big color show in Phoenix. The cars would be driven by, and we would vote on the colors we liked.”

At Toyota and other automakers, ideas for new colors come from many sources. Brown said Toyota tracks social and political events as well as trends in the economy. For instance, when the economy is down, people tend to go for brighter colors. Today’s environmental movement has made earth-tone colors popular with buyers, he said.

But Toyota officials also meet with designers and color planners from other industries _ from appliance makers to fashion designers to plumbing fixture manufacturers _ to learn what colors are popular on other items. Middlebrook said GM also does this.

“Color is a major part of the purchasing decision,” said Starling, who has been an auto dealer in Kissimmee for more than 20 years. He said once a customer decides on which model of car he wants, color is usually the next consideration.

Even though he doesn’t care for some of newest colors used by GM, Starling trusts the process used to pick them.

“It’s amazing how much time and money and effort that goes into it. I used to question some of those decisions, but they are way ahead of the curve. It’s really one of the neatest things about our industry. With the long lead times this business requires, they make very few mistakes,” said Starling.