It belongs to Eleven on "Stranger Things."

Her signature buzz cut returned for the show's fourth season.

Millie Bobby Brown couldn't shave her head this time around, so it was all up to the hair department.

TV and movie wigs like these call for an especially high standard of detail, one that keeps rising with the advent of HD and 4K cameras.

And at Wigmaker, Rob Pickens' studio, it's a long road to creating a hyper-realistic wig like Eeven's.

One that starts here.

Wig makers can't just measure different parts of the actor's head for size.

They need to record the nuances of shape, and even the template of the hairline.

That means a hyper-customized fitting.

The initial fitting with the actor is our time to capture as much information as possible.

First, they mold the precise shape of the actor's head with a head wrap, using cellophane and a lot of tape.

Then, they get even more granular, tracing the intricate growth patterns at the hairline.

All of the marking are our roadmap for the entire process.

Everything from where the actor's hairline ends to maybe we mark they have quite a slope at their neckline below the occipital.

The head wrap goes onto a canvas block, which they shape to match the actor's head using a mix of cork and stuffing.

This process is called padding the block. So, think of it like padding a pillow.

This step is laborious, but once it's done, a production shooting anywhere in the world can call in to have a wig made for an actor, even if the actor can't make it to a fitting.

We're paying attention to the direction of the lace, how it's fitting the block.

This is where we start to dart and shape it to fit the actor's head.

Just as the hairlines must be traced to the finest detail, the lace that forms the foundation of production wigs has to be a very fine denier.

They used cotton lace in the early days, and it didn't show up because you were working with film.

Film is much more forgiving than digital HD.

So, that's the thing, just as the cameras change, the hairlines have gotten finer, the lace has gotten finer.

The same goes for the silk base that's sometimes used to simulate skin under a wig.

It used to be a much heavier silk fabric.

On Eleven's wig, Rob sewed pieces of a super-light, semi-opaque silk to make it look like her scalp was visible through the buzz.

Sometimes silk isn't enough to complete the illusion, so the hair team will add a prosthetic piece under the wig's foundation.

That was the case on "Blonde," where three prosthetic pieces concealed Ana de Armas' darker hairline,

and on "Pam and Tommy," where a forehead prosthesis under Lily James' wig replicated Pam Anderson's naturally higher hairline.

The same considerations apply to the next step, the ventilating process, where they stitch in each hair one by one.

We use a variety of knotting techniques, one of which is called point knotting,

which involves a particular way of tying the hair so that the cuticle allows the hair to push down as close to the scalp as possible.

This technique allows short-haired wigs like Eleven's to be virtually undetectable.

It's also useful for the back and sideburns of men's wigs.

It's all about matching the idiosyncratic natural patterns of the actor's head.

So for example, temples either go back or down.

This particular actor grew down, so the hair was knotted that direction.

We actually tie in crown swirls, growth patterns.

We've built it and knotted it naturally so that you can part the hair anywhere on top of the head, just as you would your own head of hair.

As for the hair itself —

Hairdressers use synthetic wigs from wig shops all the time to use for background characters.

But it won't measure up for hero wigs, which require real human hair.

Synthetic hair has more of a sheen to it than natural human hair, which is kind of something we're always trying to fight.

Sometimes Rob even adds mohair to hairlines to mimic the soft baby strands that naturally grow there.

Like for Olivia Wilde's wig in "Don't Worry Darling," and Ana de Armas' in "Blonde."

The hair they choose also helps tell the story.

When making hair pieces for a film or TV character, Rob might have to convey something a wig would normally try to disguise, like aging or ill health.

That was the case for Tom Hardy's wigs in "Capone," which showed the aging mobster at a time when he was living with syphilis.

The hair texture speaks to that in the specific situation of "Capone" and the origin of the hair was actually a bit sickly before we texturized it.

Capone's hair was also thinning at that age, so Rob thinned out the density of the hair at the crown and temples, and gave him a more wiry texture in some areas, with a softer texture in others.

Then comes the coloring process, which requires a close understanding of a scene's lighting, and how that might interact with the wig.

Reds can be quite the nightmare sometimes.

If we create a red wig and they put a blue filter over the entire thing, it could look brown.

A lot of our job is alchemy, and color theory, and figuring out how that's going to play in the final product.

For example, for "Mank," we knew the entire project was going to be shot in black and white.

So, when I was doing Amanda Seyfried's wig, in choosing the blonde hair,

we ran a number of samples and actually put them on camera against similar backgrounds they would be using before we ever put a hair in the foundation of the wig,

to make sure that the blonde wasn't going to look gray, it wasn't going to look too white, it had enough dimension at the root to look like it was grounded in her head.

There were similar considerations on "Stranger Things."

Because of the way the show was filmed, everything showed up darker on screen, even Eddie's wig.

His wig was actually like a level seven/eight ash brown, but it was more of a green ash.

So, when we do more of a green ash and then they put a darker filter on it, it appears a much darker brown.

Meanwhile, some period pieces call for very era-specific hair colors that we may not see around very much anymore.

There's a very specific apricot-blonde that you notice in older women, because it was the way the oxidative dye was showing up on the gray hair.

When the actor's playing a real person, it's even more crucial to nail every detail of the wig's design from texture to color.

For the wigs in "Blonde," Rob and hair department head, Jaime Leigh McIntosh sourced hair with Marilyn's exact natural density and tightness of curl,

even though it'd later get styled into her signature pin curls.

And to achieve Pam's almost reflective shade of platinum in "Pam and Tommy," the show's hair designer, Barry Lee Moe, combined four different shades of blonde on Rob's wigs.

Those four shades created little bursts of light and shadow, preventing the high-level blonde from looking flat on camera.

We can use as many colors as we would like, upwards of five or six, depending on what we're creating, but at least three.

So, here we're just painting on a root shadow

to add a little bit of depth at the base of the wig.

For "The First Lady," the team used the same technique on the six wigs Rob made for Michelle Pfeiffer as Betty Ford.

Each of those wigs has anywhere from five to six colors to carry through the color of the previous wig into the next era of Betty,

so that way, you're not jarred, her going from a dark brown wig to a lighter blonde.

Making sure those were rooted in the same color palette was really important.

To look like it was a natural progression of the same human being over their lifetime.

Sometimes wigmakers have to make multiple versions of the exact same wig.

These are a variety of stunt wigs we've created for photo doubles, stunt performers.

They're cutting from a shot of the actor close up in the custom wig to the stunt performer shot from the side.

The hair better look exactly the same as it did in the shot before.

But creating identical wigs is notoriously difficult.

We do that through a variety of dipping processes using oxidative dyes, non-oxidative dyes, silk colors,

and different texturizing processes to make sure that we get the wig right down to the root to look exactly like the custom wig we've created.

It can get especially tricky matching stunt wigs to hero wigs with totally different hair types.

Hero wigs usually get natural hair, and stunt wigs get synthetic hair for durability.

They need to hold up for take after take of rolling down the stairs, jumping off the building, et cetera.

Synthetic hair also dries more quickly between takes, and stunt wigs need to be faster in general, with minimal application processes for comfort and safety.

You want to use a limited number of pins in case something goes awry with the stunt.

That wig needs to be removed quickly.

Wigmakers might also have to make multiple hero wigs, like Eleven's on "Stranger Things," which the team had to spend an hour and a half resetting and remolding after each wear.

To allow for this, the team alternated between three or four different matching wigs throughout filming.

When applying the wig, the show's hair department head, Sarah Hindsgaul, had to make it sit naturally on top of Millie's armpit-length hair, which was all bundled up at the crown of her head.

She didn't go with the traditional braiding method.

That would've added bulk, risking a cocoon head effect.

It's a variation off of an old school wrap called a fracture wrap, that using gauze and pins to really create tension and lay the hair as flat as possible on the head.

Even a look as simple as Eleven's required duplicate wigs, ingenious application, and painstaking work at the foundation and hairline to pull it off convincingly on screen.

The stakes are just that high with film and TV wigs.

They can either take us out of the story or keep us immersed in it.