the

Why Are Green Screens Green?

hey everybody welcome back to a think

tank it's Hannah Kristen and Jonna Daryl

and today we're talking about green

screens now we're on YouTube and there

are a lot of youtubers a lot of people

in any kind of online or streaming video

that use either all the time or from

time to time green screens that's

something that because of that people

have gotten to know but they don't

necessarily know exactly how it works or

why you use it or some of the

limitations just to clarify we are not

allocating we're not on a green screen

not on a green screen this is all

physical stuff that exists um I

understand that it's really brightly lit

but it's not actually a green screen we

do once a week we sometimes shoot in

front of a bunch of TVs yeah again not a

green screen yeah but let's talk about

what a green screen is or green

screening also known as chroma keying

that's the inside baseball term that is

the process of isolating a single color

or brightness value in an electronic

image and then making that value

transparent in post-production allowing

another image or footage to be placed

beneath the color that's been blanked

out so what does that actually mean in

practice it means if you imagine imagine

if it was all green behind us and then

it's me and Hannah you tell a computer

program to look at each little part of

the image like a pixel and to the extent

that that pixel matches green or

whatever color you choose I want you to

make it transparent and I imagine if

there was an image behind all of that

that now transparent green parts

wouldn't you be able to see it and so

you'd see through to whatever else is

there a picture of the Andes or outer

space or back then exactly

and that explains because it's that to

the extent that it's green that explains

why in bad green screening you see like

a flickery sort of like effect it's

because the lighting meant that it's not

all equally green it's perfectly lit

then it will be gone and it'll be a good

green screen or a good key key hang out

is the term you use but if it's not well

lit then it gets all like grainy and

wavy and it doesn't look real yeah and

you guys have probably done this on a

more two-dimensional level if you have

ever used like Photoshop or something

like that you can set a certain color to

be transparent

something like that so it's a very

similar sort of situation yeah yeah and

in Photoshop you can set like a region

which theoretically would be great if we

could do that but because we're moving

it's just too complicated especially

like if you have like like I have hair

you know if my hair is curly or

something then you could see through it

and make it becomes yeah bit more

difficult and so the reason and the

reason that that happens is that there's

little tiny gaps in your hair and

lighting effects hair in a particular

way that it messes with the color and so

some of the hair gets kind of greenish

off the green screen and some of the

green gets a little bit brownish off the

hair and that's why if you have

complicated hair it doesn't look as good

on me but John why is it green well like

I said you say I want it to the extent

that it's green you could pick any color

you want but look at me right now

what colors do you see a lot of white I

understand I'm pale but there's also

blue there's Browns there's a little bit

of red in my skin because I don't take

good care of myself and I'm pale so that

those are the sorts of colors that tend

to occur on people and especially and is

most important in the skin because you

can like imagine if I was wearing a

green shirt I was on a green screen the

green shirt would be invisible you'd see

through it you can tell people not to

wear a particular color of shirt but you

can't control necessarily what color

their skin is and human skin doesn't

have a lot of green in it unless they're

really sick I guess and so you can

remove green without affecting this but

if you were to remove red or orange or

yellow then the skin would start to look

weird and parts of it might be a little

bit see-through which you would not

right now that's not to say that

everybody does use green there are blue

screens as well and if an image like a

costume or an outfit has green in it you

would then have to use something like

blue yeah they were saying that in

Spider Man when they had like the Green

Goblin or whatever his name is they

would use they did use a blue screen

yeah cuz he's all green yeah and shiny

and everything yeah they obviously went

to after spider-man's he has blue on

hisses yeah not a lot of screens for

them if you keep moving the screen and

I'm messing around yeah yeah and

theoretically you could use other colors

those are by far the most common

and yeah so there are there are

limitations if you were in a huge a

YouTube context you wanted to use it you

would have to control the colors that

you wear it has to be shot with a good

camera because if I hurry you have to

have good lighting and it makes making

the video take longer once you're

finished shooting that sort of process

of getting rid of the green is really

hard on computers and takes a long time

which is one of the reasons it's not

more common that already is some people

like video game streamers you'll notice

that they'll have themselves in the

little corner of the screen it's just

them they have a program that does that

removing the green in real time as they

shoot which saves you a lot of time

rather than doing it in post-production

interesting and you guys if you watch

local news ever watch up for the

weatherman because they'll never have or

whether women because they'll never be

wearing green exactly and that's how you

know so some of them might be in front

of a big a big screen with the actual

image but the vast majority are on a

green screen and those they're limited

in their color choice but thankfully

green isn't that popular color to wear

anyway this works out that way anyway if

you have any other questions about green

screening why people use green screen

some of the limitations it's something

that we find interesting I've done a lot

of research into so feel free to post

those questions down below I'll see you

next video