Everyone knows what to expect from a TV period drama: fancy houses, fancy corsets, fancy horses. Oh, and lots of very fancy CGI.

Indeed, just because Amazon and ITV's new version of Vanity Fair, William Makepeace Thackeray's classic Victorian novel, doesn't feature superheroes or spaceships or other fantasy spectacle, that doesn't mean it can't benefit from the latest movie magic.

Whether it's making locations look beautifully period-appropriate or re-creating the Battle of Waterloo, the seven episode series features some 350 shots enhanced with digital visual effects (aka computer-generated imagery, or CGI).

The task, says Technicolor creative director Gary Brown, was "Herculean".

I caught up by phone with Brown, who spoke from Technicolor's London office, to find out more about the company's visual effects for Vanity Fair, which debuts Sunday 2nd September.

Q: Viewers might not expect digital visual effects in a period story. What kind of shots did you work on?

Brown: The majority of the work in period drama is trying to create that old-fashioned look. England is blessed with lots of ancient locations -- and there's always some monstrosity right next to them. So we do an awful lot of cleaning up or extending the set in period dramas, as well as all the boring stuff like taking out aerials and satellite dishes.

And then there's a few big set pieces in Vanity Fair, like the Battle of Waterloo. In Episode 1 they go to a place called the Vauxhall Pleasure Gardens, which was the hedonistic place of London, the place where you'd completely let your hair down, see the freaks, party and go off into the bushes and do lots of sordid things. James really wanted to open up that as a spectacle and do this kind of big one-shot wonder. We start, and we don't cut for another minute as you follow the actors through the party area. They seamlessly arrive at a point where they walk into a basket under a balloon and they rise up over the Vauxhall Pleasure Gardens and see all the mayhem below. You read that [in the script] and think that's lovely, it's something we can properly design and flex our creative muscle.

Not only did we take out modern buildings at that particular location, but we added hundreds and hundreds of people, monkeys and tightrope-walkers, and fire jugglers into the melee. When the actors walk into the balloon and the balloon goes into the air, that was actually a really complicated stitch together of two completely different shots. In the old days we might ask [the director] to just put the camera down on a tripod and not move it, and then we'll put the visual effects in, nice and easy. Nowadays we have the ability to track the camera in a very sophisticated way, so you can say to the director and the filmmakers, Go on then, go for it and we'll put whatever you want in there. It will take longer, and it will be more expensive -- a shot like that could be with an artist or two in our building for anything up to six weeks to two months -- but every now and then a sequence like the pleasure gardens is absolutely worth it.

Before even sitting down at a computer, how do you prepare for visual effects while shooting on set?

Brown: At the moment where they're getting in the balloon I needed a green screen, but the steadicam operator is pointing the camera all around, so it's not as if I can put a green screen up, because it's going to be in-shot. So we actually had a couple of guys lying on the floor with a green screen, and as soon as the camera was past them, we went, Go! And they just jumped up and pulled the green screen into frame.

Enlarge Image Robert Viglasky/ITV/Amazon

How did you plan the re-creation of the Battle of Waterloo?

Brown: The scale of it was huge, but it was tightly storyboarded, so we knew what we were trying to achieve. We [chose] a couple of fields just outside Reading, and when we came back to it, it was like a festival. There were huge marquees everywhere with hundreds of people being put into costume. We were wandering around with our bacon butties first thing in the morning, and you've got a line of about 30 English soldiers in costume, getting blood thrown over them, putting soil over them; they get their rifles and off they go.

We had different units filming different parts of the storyboard in different locations on this estate, with radio contact between us all and little 4x4 quads bringing key people from set to set. We had all the toys: drones, all sorts of different cameras, pyrotechnics. Horses shipped in from Spain with Spanish riders that were trained to do unbelievable things -- he could just say, make that horse fall over and make it look like it's wounded and it's trying to get up. And it just would, it was astonishing.

Enlarge Image Technicolor

We did that for three days. I don't know how many shots there were, just dozens and dozens and dozens, and there were visual effects in every single shot. You're essentially shooting all this stuff in the same corner of a field, so we had to cut around every single edge, every single hat, ear, nose, of every person, literally by hand. Getting rid of the tree background and adding battlefield or explosions or blood, sorting out wobbly rubber bayonets and putting solid ones in. Multiplying horses and soldiers to make them look like there's thousands of them. And then of course the big wide shots where you've got the generals on the hill looking at the whole battle. Absolutely monumental amount of work, and we could just keep tweaking. We could probably do another couple of months, but you've got to draw the line somewhere.

It sounds like an immense amount of detail...

Brown: Most feature films still pretty much are 2K, just a little bit bigger than HD, but Netflix or Amazon or Sky deliverables are 4K. I didn't even appreciate how big that was until then I saw an HD image on our 4K monitor, and my god that really is literally a quarter the size. So when you're getting really deep in visual effects, like open heart surgery on these shots, you're adding so many hundreds of digital people and simulating how their clothes move -- that gets really, really intensive on your resources.

Enlarge Image Robert Viglasky/Amazon

I remember going to a screening [for a TV project] I worked on recently, and I heard somebody in front of me say, 'I wonder if this is going to hold up on the big screen.' That's really naive -- I'm thinking, 'That's 4K, you could watch that on an IMAX. You could watch that projected on the side of the Tate Modern'. It's massive!

Has the processing power required increased?

Brown: Absolutely. Look at the bit depth -- how much information is in the picture, like a still camera's megapixels. Historically we would probably throw most of that image away. But now we work with this colour space called ACES [Academy Color Encoding System], which means that you're keeping absolutely everything. That gives the colorist the ability to do anything they want with it at the end of the process -- or even after, if the station comes back next year and redelivers this for Ultra High Definition televisions.

Each frame is something like 40 megabytes, and you're trying to play that back at 25 frames per second. It's insane to get your head around it -- it's like talking about how big the universe is.

Is there a temptation to do everything with digital effects rather than for real?

Brown: No, I think all filmmakers would love to do more in-camera. There's just the authenticity you get immediately. You're not struggling to get the right level of focus at the edge or something. Get something in-camera, then use CG to enhance -- that really is the best way to use CG.

Every now and then you need to generate something very specific, so do we go into CG or do we shoot something? Yesterday this conversation about a job that involved blood -- almost every single job we do has got some level of gore or blood in it -- and it was like, Well, why don't we just go down to Berwick Street Market, buy some fake blood from the party shop and come back and shoot it? All you really need is some way of controlling your light and a decent camera, and then you can improvise. Yesterday the artist had been sitting there for an hour or two at 60 quid an hour on a machine that's costing £100 an hour fiddling around with elements that just didn't work. It's like, Stop what you're doing, we can nail this in the next 20 minutes in the kitchen. I ran into the kitchen and we got a load of tomato sauce and Worcestershire sauce and we were throwing that around the kitchen, filming on my iPhone. And that's now being applied to someone's face on a Canadian slasher movie.

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