Two-tone revival

Features - Cover Story

Dark roofs on light vehicles or light roofs on dark ones add visual pop to SUVs, but they can add time and expense to the coating process.

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February 28, 2020

Photo courtesy of General Motors

Artists, fashion designers, and graphics specialists know how to use light and darkness to draw the eye. People’s eyes focus on the brightest spot on a canvas, dress, or printed page, so whites and other bright colors attract attention. Black can disappear in visuals, making it a favorite concealer for fashion designers.

With crossovers and sport utility vehicles (SUVs) dominating auto sales, designers are increasingly playing with contrasts to direct attention to or away from vehicle features, bringing back two-tone paint schemes that fell from favor in the 1980s. A prominent trend – different colors for roofs and vehicle bodies.

“It creates a lot more character to the vehicle. It helps us play with a slightly different proportion,” says Stuart Norris, director of design at General Motors’ (GM’s) Advanced Mobility and Experience Studio. On the 2021 Chevrolet Trailblazer SUV, the company is offering an RS model with a black roof or an Activ model with a white one. “The white roof on the Activ kind of shortens the vehicle and makes it feel tall and rugged. It plays up the truck-like characteristics. The black roof on the RS disappears, and you read much more of the lower proportion of the vehicle. That makes it feel lower.”

La Shirl Turner, head of exterior and interior color and materials at Fiat Chrysler Automobiles (FCA), says throughout the past 10 years, automakers have been adding color on the lower portions of vehicles with cladding, but the trend in recent years has been color on the top with two-toned or striped roofs.

“Vehicles are often an extension of the owner’s personality; two-tone color options and/or stripes offer our customers another way to stand out in the crowd,” Turner says.

In an age where 80% of new vehicles are white, gray, black, or silver (see sidebar, page 15), two-tone paint jobs provide a much-needed visual pull. However, the trend could lead to challenges at assembly plants.

Doubling production

“If all I want is a white car, it’s fairly simple to paint,” says Kevin O'Connor, director of Marketing and Global Product Management at Axalta Coating. “If I want a white car with a black roof, the most basic kind of personalization, it becomes more challenging. You end up having to run a vehicle through a paint shop two times.”

Manufacturers must paint two-tone vehicles the base color, cure those coatings, then mask off areas where they want to retain the base color. The vehicle then goes through the paint shop again to get its secondary tone. The process adds material costs from the base coat that gets covered by the secondary tone, energy costs for having to go through curing ovens a second time, and labor costs associated with the masking process.

More importantly, though, it ties up the paint shop – typically the biggest bottleneck in automotive assembly. Painting several vehicles twice means painting fewer vehicles per shift, a massive problem for facilities working at capacity to feed strong demand for SUVs and crossovers.

“Even the most basic version of two-tone that exists today has a pretty big cost associated with it,” O’Connor says.

Norris says GM noticed the two-tone paint trend on luxury SUVs such as Range Rovers, so it planned Trailblazer production around that demand. The company made minor alterations to its Rayong, Thailand, plant where it makes the vehicle to simplify masking, though it still uses a paint-mask-paint process. GM also uses a black applique to cover the car’s A-pillar and C-pillar to hide any irregularities caused by masking.

FCA’s Turner says Jeep’s new plant in Detroit uses a wet-on-wet process to spray liquid color paint on top of liquid primer, curing both simultaneously to reduce time and energy consumption. New equipment allows the black roof color to be applied at the same time as the primary vehicle color.

“The wet-on-wet process is an alternative coating system that’s proven and already used at Toluca (Mexico where Jeep builds the Compass SUV available with black roofs) and our Italian plants,” Turner says.

The Activ version of Chevrolet’s 2021 Trailblazer SUV features a white roof that designers say draws the eyes up, making the vehicle appear taller and more rugged.
Photo courtesy of General Motors

Digital painting

Still in development and not likely to be used for auto production for a few more years, O’Connor says inkjet printer-inspired technology may offer a solution. Axalta engineers are developing industrial paints that can be jetted onto vehicles, allowing complex paint schemes while eliminating doubling of the paint process.

“You could paint a vehicle any number of colors in a single pass,” O’Connor says. “The most extreme form would be complete personalization – somebody could ask for a vehicle with a logo or a picture of their dog. I’m not sure about the resale value of that, but you could do it.”

In Axalta’s test labs, engineers have already painted surfaces using digital paint technology, but the technology is still in its early stages, he adds. Ensuring that the paints are as durable as traditionally sprayed coatings, that jetted colors won’t fade, and that the print process is faster than the masking-and-repainting process are key to win users.

While cars covered with grandchildren’s baby photos could eventually be possible, roofs are the likely starting point for several technical reasons:

  • Low resolution – As with printers, the crispness of an image jetted onto a car surface would depend on how many dots-per-inch (dpi) of color the system could spray. It’s easy to size printer ink drops into microns, but O’Connor says getting paint that small will require new chemistries. Wide, single-color surfaces don’t require high resolution.
  • Speed – The complexity of the image and the dpi determine print speed. The smaller the drops, the slower they flow through jet sprayers, O’Connor says. Complex images will require more print time than simple color fields.
  • Flat surface – Even with their ridges and rails, vehicle roofs are mostly flat, so gravity will hold jetted coatings in place while they cure. Coatings on vertical surfaces such as body sides and doors could slump, creating ripples or roughness. O’Connor says coatings companies have solved such problems in traditional spray booths, but digital printing processes are still being developed.

“It doesn’t only require innovation for the paint but also the applicator. It’s a three-legged challenge,” O’Connor says. “Our automotive original equipment manufacturer (OEM) customers are providing some innovation, we’re developing the coatings, and the applicator companies are tailoring their devices to accommodate this.”

Coatings companies will also have to work with paint plant managers to determine where to put the industrial printers. In some cases, it could be placed after the color coat (the second paint process after priming) and before the final step, clearcoat. Clearcoat is a transparent layer that protects the vehicle’s colors, so adding the secondary color before that process would protect the finish.

Some plants, though, don’t have space for a new process between existing steps. For those, O’Connor envisions a process that would occur after the vehicle has been fully painted. Axalta already sells coatings that mix the color and clear coats, so it could use those paints to add secondary colors in space-constrained facilities.

A 2019 Jeep Compass small sport utility vehicle (SUV) descends a steep slope. Designers are increasingly using two-tone paint schemes on SUVs and crossovers to play with dimensions.
Photos courtesy of FCA US LLC

Growing trend

OEMs and paint suppliers have perfected their processes throughout more than a century of product development, and companies don’t want to spend more on painting equipment – unless consumer demand for change is too strong to ignore.

“If the take rate is low, 1% or 2% of vehicles, and if you have available capacity, it may be advantageous to simply run a second pass,” O’Connor says.

He adds that he expects demand to top 20% for SUVs and other large vehicles.

The designers agree.

FCA’s Turner says alternative roof colors allow Jeep to bring styling cues from its most-iconic vehicle into the rest of the lineup. The Jeep Wrangler is a direct descendant of the military Willys Jeep that rose to popularity during World War II. The original was either an open-air vehicle or one with a canvas top. So visually, the Jeep has often had a different roof color than the rest of the vehicle – a red body with a black soft top, for example.

Designers say black SUV roofs make vehicles look lower-to-the-ground, giving them a sporty appearance.

The Wrangler has long had various roof options with “hard top body colors to soft top colors available in black and tan,” Turner says. “The Jeep Wrangler has been a leader in this field for a long time, so it’s natural that you see the Jeep brand extending that to other products in the lineup.”

GM’s Norris says the desire to customize every product continues to grow, so automakers need to explore more aesthetic options on vehicles to appeal to new buyers.

“We’re beginning to look at our next wave of customers coming into the automotive market,” Norris says. “In Gen Z, products generally have a lot of appeal when they feel like they’re not just one of 500 on the shelf… Look at people’s lives through Instagram, Facebook, Amazon, and Apple. Everything is very monopolized, and that homogenizes product experiences. I think being able to have a more individual product, a crafted product, has a great deal of appeal for those buyers.”

Electrified powertrains also feed that trend, he adds. Electric vehicles (EVs) are quieter than traditional cars, so automakers won’t be able to differentiate products by offering radically quieter cabins. And, acceleration and driving performance will improve and become standardized in EVs, removing another vehicle differentiator.

“Where else, other than styling, are we going to be able to create a unique selling point to a customer in the future?” Norris asks.

Axalta Coating Systems https://www.axalta.com

Fiat Chrysler Automobiles https://www.fcagroup.com

General Motors https://www.gm.com

About the author: Robert Schoenberger is the editor of TMV. He can be reached at 216.393.0271 or rschoenberger@gie.net.