Working with the idea that being stricken with a cold turns us all into big pudgy, drippy, cranky babies, agency Ammirati Puris Lintas and Sparks director Peter Montgomery created just such a creature for a recent spot for NeoCitran.

The spot features a sleepless cold sufferer going through the lonely nocturnal journey up to bed with the curing elixir in a cup in his hands. Initially, we see the sick fellow in parts – a shadow and a foot on the stair, a hand on the railing and around the cup. We hear a grunt, but it’s not until we are confronted with an unmistakably real baby face attached to a big-person’s jammies and bathrobe do we see that it is an adult-sized baby walking through a properly scaled hallway and into his room.

It’s a simple gag, but numerous imperceptible elements were combined to create the spot’s eerie effectiveness. It’s hard to dissect what’s wrong with this striking picture; the fact that the baby walks like a grown man, for instance, might not be obvious, but it’s one of the elements that add up to (depending on your feelings about giant babies) a big chill or a big laugh.

Montgomery, who has a wealth of experience in visual effects and larger-than-life children, used a combination of elements to bring that peculiar realism to every detail.

‘The trick was to try and create a believable baby that didn’t simply look like a larger real baby, but that had something quirky about it,’ says Montgomery.

The director decided on the walk-like-a-man principle straight away and cast an adult actor as well as a one-year-old, combining not only the two but a number of added elements, including prosthetic baby hands and feet to create the composite character.

The actor was fitted with a padded body suit to create the plumper proportions of a baby and Toronto’s Caligari created the prosthetic hands and feet to incorporate that realistic pink chubbiness.

The actor was shot first on a dark set wearing a green sock on his head with tracking marks made with reflective Scotch light tape to provide a visible tracking reference in low light. ‘So what you have at this point is a man in a padded body suit wearing a bathrobe with giant baby hands and feet and a green sock on his head: it was an interesting looking shoot,’ says Montgomery.

Takes from that shoot were selected and the baby was shot with a green screen the next day. Because of some of the larger proportions of a baby (a baby’s head being twice as large, proportionately, as an adult noggin, for example), Montgomery took the information from the adult shoot and scaled it in half.

To achieve the effect of the baby entering his bedroom and turning to close the door, Montgomery shot the baby on a turntable to create the corresponding move, leaving the baby to focus on strictly ‘performance.’ Lighting cues also had to be added to address the movement from the cool light of the hall into the warm light of the bedroom, and footage of the computer-decapitated baby and the light change were tracked onto the actor’s body.

Montgomery says his past experiences, including as effects camera on Honey I Blew Up the Kid, convinced him that the only sure way to deliver a realistic baby face was to use a real baby; and a number of subtle elements were added to heighten the effect.

Since having a baby cough on cue would likely involve inhumane use of cayenne pepper, Montgomery deconstructed the elements which comprise a cough and recreated them. The director used footage of the baby blinking and bobbing his head, together with the actor’s shoulders and the prosthetic hand brought up to the mouth composited together to create the effect. Again, to make this shot more convincing, the baby’s naturally occurring wide eyes were removed and a lidded eye effect was composited in with modified footage of the baby’s blinking eyes.

‘There were a lot of subtle things going on,’ says Montgomery. ‘You couldn’t just drop the baby’s head in. It was figuring out how to shoot it so the perspective and scale were correct, how to get the performance to match between takes, because a baby does what a baby feels like, plus lighting changes and so on.’

Montgomery says (the late) Daily Post added further elements to create the seamless overall look. ‘All of it comes and goes and you don’t notice it, but it looks seamless because there was a lot of work that helped glue it all together.’

The artists: Montgomery directed with dop Nick Allen-Woolfe behind the camera. At Daily Post, Peter Macauley was editor and post supervisor and Craig Smalls composited. Louise Macintosh created the prosthetics at Caligari.

The gear: Daily Post used Adobe After Effects for compositing.