Inside a 110,000-square-foot warehouse in northeast Los Angeles, Gregg Bilson Jr. is showing me his blood. There's drinkable blood, chunky blood, dried blood, and flowing blood, all sitting in tidy rows on a display shelf. Puddles and pools of blood — resin blood — ​of varying sizes are affixed to a nearby wall. Each has its own consistency, color, and refractive properties, which Bilson says are important distinctions when your customers are as likely to have a favorite blood guy as they are a favorite restaurant.

Bilson owns and operates Inde­pendent Studio Services, one of the largest prop houses in the country. If someone interacts with an object on-screen — and it's not furniture or decor — he and his 160 employees make, rent, or sell it, be it refurbished arcade cabinets for Pixels, Ant-Man's grappling hook and belt components, or vital fluids. Maybe because he manages more than a million fake objects, Bilson tends to talk in lists and uses the word literally a lot. (A typical sentence: "These are skates, office devices, books, phones, typewriters, recording devices, babies, perambulators, camping stuff.") His father founded the company out of his Culver City garage in 1977, before moving the business into a former Lockheed hangar in Burbank. Twenty years ago, he handed over the firm to Bilson, who had served as a prop master on Moonlighting, Doogie Howser, M.D., and NYPD Blue, among others.

My fake-blood tutorial is taking place in what's known as the Expen­dables Department. On another shelf are 2- and 5-pound bags of lactose — ​the milk sugar that actors inhale when a script calls for coke to be snorted. Nearby are jars of something called Schmere. Made from clay minerals, it is essentially sanitary dirt. "A $20 million actor doesn't want to roll around in real bacterial filth," Bilson explains, "so you have to make them look filthy with clean stuff."

Bilson, a fit 50, is wearing a MAMMOTH, I LOVE YOU T-shirt and cargo shorts. He points out the manufacturing wing, where the drone of heavy machinery mingles with the smells of vinegar, leather, and oil. Employees are spray-painting guns for the next Star Trek movie. A foam piano top lies on a workbench. Close by, the mold used to create Loki's staff from The Avengers is locked in a metal cage. The company works on some 3,000 projects a year — not just films and TV shows but also commercials and the occasional church play — many of which require thousands of props. Bilson says he counts on about 20 percent of inventory being in use at any given time. Were the props suddenly to come back all at once, he would have no place to store them.

"If you do it wrong, everybody is going to crucify you," he says of his job. "If you do it right, nobody notices." Doing it right has become increasingly difficult because of high-res cameras and screens. Fake knives must now look sharper, dead bodies must appear deader, and God help the prop master who uses a rifle from the wrong era in a historical war drama. Bilson tells me how the VCR changed the business in the 1980s. When he was working on Doogie, a fan paused the opening title sequence and discovered that the newspaper articles it panned over were gibberish. The show's creator, Steven Bochco, ordered the sequence redone at a cost of tens of thousands of dollars, Bilson says, and that was more than 25 years ago. These days, a fan can examine words not just in a close-up title sequence but also on a piece of paper held by an on-screen character.

As we pass by a cart piled with what appear to be adolescent-size skeletons, Bilson points out a row of meat on top of a 10-foot shelf, in different sizes and cuts. "You can't have a bunch of raw meat outside for two or three weeks in the summer," he says, "so you have to create a bunch of fake stuff and then bring in a small portion of the real stuff on a daily basis for close-ups."

Behind a keypad-secured metal door is a room lined with hundreds of guns: muskets, bolt-action rifles, a Mateba semi-automatic revolver, flamethrowers, rocket-propelled grenades, as well as replicas of Lee Harvey Oswald's 6.5 mm Carcano carbine and John Wilkes Booth's .44-caliber derringer. Bilson has earned a reputation in the industry as someone who can make or get any gun you need. He has been so successful at manufacturing both sham and real guns that he also sells and rents them to law-enforcement and government agencies. He's provided the Department of Defense with rubber rocket-propelled grenades and AK-47s for training exercises and has arrangements with police departments to test new weapons systems for their SWAT teams before they buy them.

As we make our way past a Sony film camera and its fake twin, Bilson stops. "Did I mention the time I decided to figure out which prop had pulled in the most money?" The company's tracking software provided the answer. "It was a male juvenile dummy," he says. It rented for $48 but over the years had made the company $168,000. "The first thing I said was, 'Make more dummies, guys. We want more dummies to rent.'"