Reality is overrated. Where would Game of Thrones be without its dragons? Or Stranger Things without the Upside Down? Or Lost in Space without, well, space (and that robot)? Shows like these are unimaginable without computer-generated effects. But not all shows are so heavily dependent on them, and those shows that aren't as dependent on them have their own Emmy category: “Special Visual Effects in a Supporting Role.”

Gotham was last year’s winner in this category and is nominated in it once again this year. As visual effects supervisor Thomas Joseph Mahoney told SYFY WIRE, effects work on Gotham can range from matte paintings and city extensions to enhancing explosions and creating Scarecrow’s nasty fear toxin. This year’s nominated episode, “That’s Entertainment,” also involved killing off Jerome and stranding Oswald in a blimp.

So let’s talk about making the blimp. Poor Oswald!

The blimp was a big thing in this episode because we had Oswald and one of Jerome’s cronies flying the blimp, and that all had to be CG. We always talked to the show creators — Danny Cannon, Bruno Heller, and John Stephens — about what they want. There was an actual practical gondola (the part which holds the passengers and crew) that they shot for the interiors of Penguin and the pilot, and so we riffed off those initial designs to make a blimp that’s not quite retro, not quite steampunk, but kind of borrows from both of those.

From there, we just build it in CG, and when we shoot the shots, we tell the actors, “Hey, look up there! There’s a blimp!” And to their credit, they react like there really is a blimp. Ben [McKenzie] and Donal [Logue] are really good at pretending something is there, when there’s not.

Video of Gotham - Penguin gets put in Jerome’s blimp with the laughing gas

Do you ever get to suggest visual effects ideas which aren’t already scripted?

I think the final pullout on Penguin would qualify. I don’t think we were initially planning to come out nearly as wide. We were going to just come out wide enough to show that he was in a blimp in the sky. And during the editorial process, we have what’s called a visual effects spotting session, and we put our heads together and we said, “Oh, come on! We should just keep pulling out until we see buildings in the foreground, the river, and the bridge.”

Everyone got on board with that and thought it was a great idea. I’m certainly not taking credit for that, because I don’t remember who first suggested it, but when we were spitballing ideas, we said we were going to keep pulling out until we see all of Gotham. It’s more comedic to leave Penguin screaming in the gondola, and it also gave us a chance to see Gotham in all its glory.

Do you walk around New York looking for things that could be Gothamized?

Always. [Laughs] Early on, Danny Cannon and Bruno Heller said to us that Gotham should always feel like there’s a storm coming, so we always start with that feeling. Gotham is not a blue sky, happy place like Metropolis might be. We even tried to ramp that up a little bit over this season. So that’s our first step – trying to get the atmosphere. At night, we tend to have a moon with clouds around it.

Whenever I’m in New York City, I look around and say, “That’s a good Gotham building. That’s not a good Gotham building.” Even when we’re shooting, I’ll look in the background and say, “That building? We can add to it and make it cool, make it Gotham.” The Chrysler Building is a good Gotham building, but that’s too recognizable. The Empire State Building is a relatively good Gotham building. But glass-and-steel structures like the new World Trade Center, that’s definitely not Gotham.

Anything with a modern feel is not Gotham. Water towers are very Gotham. Brownstones are very Gotham. But square blocked-off cement buildings are not Gotham. A lot of lower Manhattan, before you get into the Financial District, is very Gotham.

We refer to the style internally as gothic Art Deco. It’s the 1920s, 1930s architectural feel, but really gothic with spires and gargoyles. We often do use existing buildings and make them weathered, or add to them. We also create complete, whole CG buildings from scratch. My hope is that anyone who lives in New York looks at Gotham and goes, “I kind of recognize it, but it doesn’t quite feel like New York, either.” If people who live in New York don’t recognize it as New York, then we’ve done a good job as far as I’m concerned.

Paisley Park, in this episode, is just under the Manhattan Bridge. We didn’t do much to it for the down angles. But when you see up, we changed the sky a great deal and we added buildings in the background. If you look with a real keen eye, you’ll see it’s the same place we shoot a lot of the exteriors for the Gotham police department.

Video of Jeremiah Turns Into The Joker | Gotham 4x18

One of the seminal moments in this episode is when Jeremiah breathes the gas and becomes the Joker…

We always tend to be aware of those big moments, and we always try to put our best foot forward when they come up. And the Scarecrow gas is always fun to do. Once Scarecrow puts his emitters up in somebody’s face, we track it with fluid simulation software. It’s all computer-generated, including when it collides with somebody’s face and swirls around. We have people dedicated to doing just that. It’s tricky, because you’re simulating how steam and smoke act in the real world. If we don’t do it quite right, it doesn’t feel right. There’s a lot of nuance to it.

When Jerome dies, how did you shoot it? Was he hanging over a real alleyway on wires, and you did wire removal? Or did you shoot it on a green screen?

When Jerome falls to his death, it’s a big showdown between him and Gordon, and Gordon has to shoot him to prevent him from dropping the gas. Then he has his last moments where he’s more or less getting in his last licks in at Gordon, where he basically lets him know that he’s got a plan in place which will happen whether he lives or dies. Gordon’s a human being, so he’s trying to save him, too – he’s not just going to let him die.

But the way we do those, we shot Cameron Monaghan over a green screen. He’s only up maybe two feet. Then we took photography of the area around the space this takes place in this episode, and we build a 3-D replica of that, so we can put him into a 3D version of the alleyway where he falls into. The invisible effects like that are the most fun, when people don’t realize we did anything. Then you feel like a magician, like you fooled somebody!