Turning back the hands of time to 1900 was no mean feat on “The Knick,” which premieres Friday at 10 p.m. on Cinemax. The drama about a struggling New York City hospital was filmed in 70 days in a studio in Greenpoint, Brooklyn, and on the streets of the city.

Boys High School in Bedford-Stuyvesant provided the exteriors for the show’s Knickerbocker Hospital, where John Thackery (Clive Owen) and a staff of doctors deliver babies, repair hernias and treat the diseases of the day — typhoid and syphilis among them. A sparkling example of Romanesque Revival architecture, the school was designed in 1891 by James W. Naughton. It is both a city landmark and on the National Register of Historic Places.

“It is a beautiful building,” says Howard Cummings, the show’s production designer. “The script was talking about an older hospital, supposedly on the Lower East Side. Period-wise, we were going to be in 1900 to 1901, so the building was going to have to be from the 1880s. That kind of Victorian architecture was perfect.”

Finding a city street to approximate one of New York’s poorer neighborhoods was easy enough — the Lower East Side boasts enough tenement architecture to inspire any set-dressing team. “We did remove air conditioners on the lower floors,” Cummings says. “All others had to be removed digitally. Everything at head level has to look realistic. Above head level you can get away with a lot.”

Broome Street, Lower East Side

In this scene, characters shop for chickens and turkeys, kept in baskets in the foreground. “They sold livestock in the streets. Chickens, turkeys, rabbits,” says production designer Howard Cummings. Canvas awnings and fake facades camouflage contemporary plate-glass windows and awnings.

Broome Street, Lower East Side

What you’re looking at is an outdoor shopping mall, with vendor carts and characters carrying a piece of furniture they’ve just purchased. “Almost 90 percent of the world’s clothing was coming out of the Lower East Side [at the turn of the 20th century],” says production designer Cummings. “The buildings were jam-packed with people sewing. The street looked like a giant farmer’s market.”

Creating this scene for a two-day shoot was an intricate task. “We dealt with every business on those blocks,” says Rob Streim, location manager. “Restaurants didn’t really want to close down,” says Cummings. “There was a laundromat that had no interest in shutting down. If they had plate-glass windows, we made fake facades with bay windows to put product in, and the owners could walk through fake doors to still do business. When I couldn’t take down awnings, we made canvas skirts to hide them. I would hang laundry where I could.”

Madison Street, Bedford-Stuyvesant

In this scene, character Lucy Elkins rides a bicycle to work while two street sweepers clean the sidewalks behind her. The bike is a fully restored Gormully & Jeffery Rambler from 1900 that was purchased from and restored by Via Bicycle in Philadelphia. The wooden wheels and crocheted fenders were custom-made.

The street sweepers in the background are an interesting bit of New York history: “The spread of tuberculosis was pretty prevalent in the descriptions of the streets in the 1880s and 1890s,” Cummings says. “There were mountains of horse manure everywhere in 1896. In order to stop the spread of disease, the White Wings were created. They were the city’s first sanitation workers. They were also responsible for snow removal.

“I also added gray dirt to the street and sidewalks to blend the sidewalks away, because there would have been flagstones there.”

Front Street, South Street Seaport, Manhattan

“This is a super-historic street,” says Cummings. “You really can’t change anything. It also has weirdly flat building facades. The pipe railing on the left is OK, but I had to put walls up when buildings were too modern. The man on the far right in the peacoat and the dark wool hat is Steven Soderbergh, who was the director, cinematographer and editor on the project.”

Boys High School, Bedford-Stuyvesant

The show did seven days of shooting at the landmark Romanesque Revival building. Air conditioners were removed and window guards had to come down. “Boys High School has an engraved plaque in sandstone above the entrance. I liked the way it looked,” says Cummings. “We made a board sign with raised letters that was textured to look like sandstone. Because the building is historic, you can’t invade anything on the facade that’s permanent, so we created a rig and hung it off the plaque. The visual effects supervisor had to blend it with the original facade.”

The doctors in the operating theater

They didn’t have scrubs in the 1900s. Instead, the doctors wore operating gowns that were their only protection from arterial sprays and the like during surgeries. These gowns are floor-length cotton twill. The smocking in front comes from the yoke, and the gown has a sash that ties in the back.

“The white, the dark in the room and the blood are really essential to the show,” says costume designer Ellen Mirojnick. “There would be many operations during the production, and we went through hundreds of gowns. If they became too bloody, we could change them easily. We treated it as if we were supplying a hospital.”

Nurse Lucy Elkins, Eve Hewson

To design a nurse’s hat for Lucy Elkins (Eve Hewson, daughter of pop star Bono), Mirojnick looked at what nurses wore in hospitals in Baltimore, Boston and New York. The stripe on Lucy’s hat indicates that she is an attending nurse.

As for her dress, it’s a shirtwaist in lightweight cotton twill. There are pin-tucks on the sleeves and extra-wide cuffs, while her medical supplies are kept in a leather purse that hangs from her apron.

Lucy, as was the custom of the day, wears her hair up. “Women did not wear their hair down in public,” Mirojnick says.

Lady in blue

Abby Alford (Jennifer Ferrin) is a patient and ex-lover of Dr. Thackery’s who comes to him in the most fearful state. A disease she contracted from her husband has made part of her face rot. To present such a high-born lady in such perilous circumstances, Mirojnick says she wanted to accentuate her elegance. All the costumes on “The Knick” are custom-made.

“Although her condition is quite startling, there was no reason not to dress her as she would ordinarily appear,” says Mirojnick.

Abby wears a silk brocade afternoon walking suit in deep purple-blue with a silk and lace blouse and a soft, creamy lavender jabot. The gloves are gray suede. For the hat, Mirojnick says, “We made a construction of velvet and silk ribbons. It’s a pretty lady’s hat.”

Mirojnick did extensive research on fashion from the mid-19th century through 1901 and decided to lean toward the more modern end of the period.

Dr. Algernon Edwards

Harvard-trained Dr. Edwards (Andre Holland) is a study in continental elegance. This three-piece suit is navy-caramel tattersall worsted wool, with a pocket watch attached to a fob that goes around a button on the vest. He has a detachable wing-tip collar on his shirt, which has a fine caramel stripe. He wears a derby with a rolled brim that gives it a sculptural look. The shoes are a Stacy Adams boot that was in existence at the turn of the century.

“Dr. Edwards was educated in Paris. He’s forward-thinking and goes for something more fashionable than the other doctors,” Mirojnick says. “Nobody else wears patterns.”