The Fourth of July just wouldn't be the same without the colorful peonies, waterfalls, and comets that burst across the night sky above wowed crowds. But designing fireworks and their choreographed displays is a labor-intensive, dangerous job that requires the imagination of an artist and the precision of an engineer. Mental Floss talked to two experts in the field to learn how fireworks designers plan their shows, the history and the chemistry behind their displays, and why you don't necessarily want more bang for your buck.

1. THE ROOTS OF THEIR PROFESSION GO BACK OVER A THOUSAND YEARS.

Humans have been adding bright, noisy explosions to their celebrations by setting fire to chemicals since at least 9th-century China. The very first fireworks were little more than quick orange bursts emanating from bamboo rods packed with charcoal, sulfur, and potassium nitrate and tossed into bonfires. Slowly, these contraptions progressed into flares cannon-fired into the sky by “firemasters” in medieval England. By 1830s Italy, the use of metal salts such as strontium, barium, copper, and sodium added vivid reds, greens, and blues to firework displays—a precursor of the brilliant hues we see today.

2. THEY CONSIDER THEMSELVES ARTISTS.

“Fireworks are our paint or our clay, and our canvas is the night sky—or a building, or a bridge, or a waterway,” says fifth-generation fireworks designer Phil Grucci, CEO and creative director of the Bellport, New York-based Fireworks by Grucci. The company has created fireworks displays for seven consecutive U.S. presidential inaugurations, Olympic games in Beijing and Los Angeles, and commemorations such as the centennial of the Statue of Liberty, among other events. “Working with space, understanding color and the dynamics within the fireworks, what moves very quickly, what sounds very loud, what sounds very soft, what is subtle and elegant”—all of it takes an artist's touch, Grucci says.

Pyrotechnic designers “can visualize exactly how various fireworks devices will burst in the sky,” says Julie Heckman, executive director of the American Pyrotechnics Association. That means they know "how high [fireworks] will reach their apex and burst, how wide they will spread, and how long the effect will ‘hang,' or linger. They can then choose other fireworks to burst above, below, or on each side of an effect to create the image they wish to see across the sky."

Of course, "painting" with fireworks is a little trickier than using acrylics or oils, since the medium is explosive. "The difference [compared to painting] is that we’ve got something that’s dynamic, that moves, it’s constantly moving and it’s very temporary," Grucci explains.

3. THEY START WITH A PAPER SKETCH.

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Old pros like Grucci may know from experience how certain fireworks will look together against a backdrop. But he still sketches out each segment of every show he designs with colored markers on paper. From there, he works with his team to set the show to music, then choreographs it using software called Visual Show Director. Next, his programmers create a script in SolidWorks and/or AutoCAD. “In the past,” Grucci explains, “we scripted it all on a piece of paper, and the pyrotechnicians installed the hardware from that same piece of paper." Now, he says, they can be "taking advantage of the computer age, to visualize [a show] to see whether the product works as you’ve designed it.” Finally, Grucci’s team generates the computer file that will electronically ignite the fireworks at showtime—much safer than the days when a human had to ignite the fuse.

But Heckman says that although the technology is useful, it's made fireworks performances a little more homogenous. "Before electrical firing, computer choreography and a reliance on imported product [mostly from China], I think fireworks companies' unique style was much more prevalent," she says. "Technology has somewhat leveled that out." A few companies do still have distinctive styles, she notes—even if those differences are usually only apparent to true fireworks aficionados.

4. SOME THINGS ARE STILL DONE BY HAND.

A fireworks cartridge contains a series of pellets called stars, which are cubes, spheres, or cylinders about an-inch-and-a-half long filled with explosive materials and color-producing chemicals and metals [PDF]. A star’s colors are formulated via computer, then pressed into a pellet shape by machine. But when it comes to arranging the stars in the casings that will be fired into the night sky, it's usually human hands doing the arranging. The pattern laid out inside the casing determines the pattern of the explosion—a heart-shaped firework blooms from stars arranged in a heart shape—and according to Grucci, automating the task to account for the enormous variety of available patterns would be too expensive. The task can be labor-intensive, since a single shell can contain hundreds of stars.

5. THE VENUE DETERMINES HOW THEIR SHOW WILL UNFOLD.

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It's as true in fireworks as it is in real estate: It's all about location. That’s partly for reasons of safety—Heckman says that every show has to follow industry standards for “tables of distance,” which “mandate the size of the largest shell that can be fired safely from a standpoint of fallout distance to spectators, and also public highways, occupied buildings, and public roads.” She says there's a complex regulatory scheme that dictates the type of products that can be used per type of venue, as well as when shows can begin and end.

But the site is also an integral part of the beauty and impact of the show itself. "We’re very aggressive in looking at structures, and trying to highlight their key features," Grucci says. “Whether it’s a tower, whether it’s a bridge, we will be [scouting from] the very highest point of that. If [a structure] is horizontal, I know that we are going to capitalize on the entire width of it. I could be easy and say, 'put some fireworks to the left and right side of a bridge.' But that’s not good enough. We have to take advantage of the undercarriage of a bridge, the steel cables that hold its towers together, and highlight the entire structure.” Grucci says he'll often calculate the entire surface area of a structure, so he can make sure he's taking advantage of every square inch.

6. THEY MATCH THE FIREWORKS TO THE MUSIC.

Not all fireworks displays have music, but when they do, the score and the effects should complement each other—not clash. A delicate classical piece may call for smaller, quieter fireworks, while a piece like the "1812 Overture" might fit bigger, louder bangs.

"So many of the [effects] we’re working with, they may have a baroque feel to them," Grucci says. "They’re very bold and strong and very in-your-face, but then you have that very elegant feel to some of the fireworks, that you would never put onto the canvas when there’s a rock-n-roll sequence on. When the product is so simple or so elegant, it would not match that tempo or that thematic."

7. THEY HAVE HIGH-TECH TESTING FACILITIES.

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Say you want to create a streaking green comet with a silver twinkling tail. “We’ll make that on a small scale, then we’ll test it at one of our two test sites, in upstate New York or in Virginia,” Grucci says. “Our pyrotechnicians are in protective bunkers and we have high-speed video cameras, wind meters, and dB [decibel] meters for noise. We record everything that we’re testing, so that we can look back on that and analyze it. I can’t tell you how many times we’ve failed. But we failed at the test site—never on the performance stage.”

8. THEY DON'T REPEAT THEMSELVES.

“My desire is to always make something that’s different,” Grucci says. He tries not to repeat a particular scene more than once in a performance, let alone repeat a whole show—although he notes that it helps that the "canvas" is always changing: “Even though we may use a particular beautiful color scheme with a metallic glitter, putting that on the Washington Monument as opposed to [over] an open baseball field—those are two completely different visuals.” One of his newest innovations turned up in the presidential inauguration in January 2017: a 600-foot by 700-foot display behind the Lincoln Memorial, made up of a series of 800 fireworks shells that burst in sequence into an American flag. “The color red [we used] is from a formula that is probably a few hundred years old," he says. "But delivering these little red dots on the sky at these [different] heights is what [allowed us to create the flag].”

9. LESS CAN BE MORE.

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"Sometimes people get caught in the trap of thinking that more is better," Grucci says, but when it comes to the number of fireworks in a performance, it can be exactly the opposite: More shells equals more smoke, which can white-out the night sky. "When you put too much in the sky ... you’re not really allowing the medium to display the beauty of what the product is about," Grucci says. (Plus, the metallic particles in fireworks smoke can pose a health risk for people with asthma or other health problems, which means it's wise to limit smoke where possible.)

10. THEY HAVE THEIR OWN LINGO.

Fireworks designers love to borrow from nature for the names of their displays. In addition to peonies and chrysanthemums, which both burst into circles (chrysanthemums have longer tails), there are willows (bursts with trails of gold or silver stars), falling leaves (glowing embers that flicker as they tumble to earth), fish (which leave little squiggles of light), spiders (a hard burst with straight, flat legs), and palms (which bursts up and out in a shape like its namesake tree). But there are also fountains (showers of sparks, sometimes also called gerbs), comets (several long trails of sparks), crossettes (a comet that breaks into other comets, usually creating a cross shape), dragon eggs (a delayed crackle effect), salutes (a loud noise without a display), and strobes (which burst with a blinking effect).

While creating their show, fireworks designers may work with cake (a single fuse that lights several fireworks in a sequence), whistle mixes (a combination of potassium and sodium benzoate that burns noisily), and dark fire, which is used to allow a star to change from one color to another (it gives off no light as it burns, allowing the new color layer to ignite below it). They hope to avoid flowerpots (which burst prematurely) and stars that are blown blind—or fail to ignite at all.

11. DANGER IS (UNFORTUNATELY) THEIR MIDDLE NAME.

Fireworks manufacturing presents an enormous danger. In 2016, Slate reported on a preponderance of deadly fireworks-making accidents in China—with an average of 400 workers in fireworks production plants dying every year between 1986 and 2005. Elsewhere, fewer accidents seem to happen than one might expect from the mixing and storing of combustible chemicals. According to Heckman, in the U.S. at least, that’s because the Occupational Safety and Health Administration (OSHA) “stringently regulates the manufacturing process, including personal protective gear, and employers must train their personnel on the hazards and the [kind of gear that’s] required.”

“We’re mixing powders to create explosive compositions that have to be handled very delicately," Grucci says. The work has to be done in a non-sparking environment (one with special tools and materials that reduce the risk of sparks), and in a room that has plenty of exits. "[You don’t want to be in a] big, giant room filled with fireworks and there’s only one door to get out," Grucci says. Workers in their factory wear conductive shoes, which conduct static electricity through the footwear and into the ground, "because the environment is very dry and you wouldn’t want to walk across the floor and touch something and have an arc spark that goes to a box of open powder and explodes on you.”

Safety is paramount for Grucci, who lost his father, James, in a massive industrial accident in 1983 at the family fireworks plant on Long Island. He says that the secret to safety, from manufacturing through installation, is to “be consistent and never cut a corner.” He says his grandfather always told him, "As soon as you think you know it all, or you want to start cutting corners, [that's] when potentially you’re increasing your odds of getting injured or possibly killed."

12. SOMETIMES THEIR FAVORITE WAY TO WORK IS SMALL.

Yes, it’s a challenge to produce a 30-minute fireworks show off five barges in the middle of Manhattan’s East River—but intimate shows present their own set of hurdles. Grucci mentions a Dolce & Gabbana fashion event held around Lincoln Center’s fountain that he created pyrotechnics for this spring. The flaming bits were a mere 15 feet from the audience and the clothing that was showcased in Lucite boxes. In that kind of scenario, “You can’t afford to have the hard outer casing or the inner paper wrappings” you’d use at an aerial fireworks event over the river, Grucci says. “The last thing you want is debris falling on the audience.” The solution: stationary fireworks comprised of titanium and aluminum particles of a sub-micron size, which burn quickly and don’t sustain heat for more than a few milliseconds—sort of like a sparkler.

13. THEY BREAK RECORDS.

World fireworks records include the largest fireworks display: 810,904 of them, fired off on January 1, 2016 in Manila, Philippines. And the most shells launched per minute: 479,651 in Dubai, United Arab Emirates (UAE) in 2013. And the longest fireworks waterfall (a long, glittering shower of embers): 11,539 feet, 5 inches, at a fireworks festival in Fukuoka, Japan, in 2008. On New Year’s Eve 2018, the Gruccis broke the world record for the world’s largest single aerial shell at a show they produced on Al Marjan Island in UAE. Weighing 2397 pounds, it was the culmination of almost 40 years of Grucci family trial and effort. “My father attempted the world record for the largest firework back in 1979 [with] a 42-inch-diameter white magnesium cascading flower that we displayed down in Titusville, Florida," he says. "Guinness gave him the world record, but it didn’t launch to the height or break to the size that he wanted it to. He always wanted to retry that and I had the opportunity this past New Year’s Eve to give my family another crack.”

14. THE FUTURE IS BRIGHT (OR PASTEL).

Research is underway on fireworks that are quieter—which could cause less stress to animals, children, and those suffering from post-traumatic stress disorder—as well as fireworks that are kinder to the environment by using cleaner, nitrogen-based fuel.

But those aren't the only innovations shaping the future of fireworks. Shapes are changing, too; look for letters and corporate logos. Designers now also have a host of softer and more diverse colors at their disposal. “In the early ‘80s we started developing colors in between ROYGBIV, the basic colors, so now we can produce lemon and tangerine and chartreuse and aqua and every color within the spectrum,” Grucci says. They do so by fiddling with the purity of the metals used and the size of their particles—which also change other parts of their overall effect. Large particles of metals like titanium, iron, and aluminum result in large “splinters” and a glittery effect, Grucci says, while smaller particles lead to fewer splinters and “a very bright light.” He notes that at this point, they can "get pretty much any Pantone color" in a fireworks composition.

15. THEY LOVE TO SEE AMAZEMENT ON THE FACES OF AUDIENCES.

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“I think a crowd, in general, appreciates a lot of action—variations in colors and noise; and pattern shells such as smiley faces, hearts, and dice are always pleasers,” Heckman says. According to Grucci, “This is a very serious business. But it’s colorful and it’s beautiful and it has great, great energy. When we go to a performance, we can see an 80-year-old man and a 5-year-old granddaughter watching the show and their expressions are pretty much the same.” In that moment, “They both [become] children.”