Formula One teams have been stripping paint from the cars, proudly presented before the season started, as they seek to go faster.

McLaren, Aston Martin and Williams were among those at last weekend's Emilia Romagna Grand Prix in Imola with notable expanses of raw, black carbon fiber replacing previously liveried areas.

New rules for 2022, with the introduction of larger wheels and increased use of standard parts, have left some struggling to get down to a new minimum weight limit of 798 kilograms.

Every excess 10 kilograms translates into about 0.3 seconds of lost time per lap.

"With the halo, the bigger tires, the longer cars, we were all overweight. I think all but maybe one team," McLaren boss Zak Brown told Reuters.

"When you’re overweight you do everything you can to save anything you can. And it’s all incremental."

Brown said some sponsorship deals, such as McLaren's with Google's Android, had accelerated the process of stripping paint.

"Our engine cover was initially papaya but that was before we landed Google as a partner. We took the opportunity: "Hey, you want black? Fantastic’," he said.

"We didn’t modify anything that wasn’t kind of in line with our brand or what a partner wanted. But it saved some weight. Not a lot but it’s about finding a little bit in a lot of different places."

Saving weight by going back to bare metal, or carbon fiber has a long history in motor racing.

According to lore, the original 1930s Mercedes "Silver Arrows" acquired their nickname when the cars raced with bare aluminum bodies after the team removed lead-based paint to shave off a kilo and come in under a maximum weight.

The paint on a Formula One car weighs around 6 kilograms, according to Alfa Romeo team manager, Beat Zehnder.

Aston Martin's technical head Andrew Green said last month that removing some of his car's green paint had saved 350 grams.

Back in 2016, McLaren sponsor AkzoNobel said painting each car involved 6 liters of paint and 3 liters of gloss lacquer totaling more than 8 square meters of painted surface.

Dave Robson, Williams's head of vehicle performance, was reluctant to quantify the exact gain from removing paint but said it was "meaningful."

"The paint might be light but to get a good finish you end up doing quite a lot of filler work and prep on the bare carbon before you put the paint on," he said.

Robson said stripping off paint was the fastest way to remove weight and even if a car was below the limit it was still beneficial to have an extra saving so the team could add ballast to improve balance.

"It will be expensive and time-consuming to find the weight (saving) some other way," he said, indicating the bare look was set to stay even if marketing departments were less happy.

"The car has to have some visible personality but at the same time it's in the sponsors' interests to make it as quick as possible."