WEDNESDAY WONDER: What's Up With That Yellow Line on the Football Field?

What sorcery is this???

October 31, 2018

While watching the Packers game this past weekend with my wife, she posed a question that I’d never really thought of myself.  She pointed out the “Yellow Line” on the field and asked what it meant.  I told her it represented where the team with the ball needed to get in order to have a 1st down…she said “you mean, the line isn’t REALLY on the field!?” 

“Nope.”  I said. 

“How do they do that!?” She asked.

It was a logical and excellent question, and made me DO they do that?


© Jake Roth-USA TODAY Sports


I can’t remember a time when it WASN’T on the field.  I’ve seen the same lines on the field of both baseball and hockey games as well…

Turns out it’s basically the same technology that TV weather people use to show you the forecast, a video production technique called “chroma key” – or you might have heard it referred to as a “green screen”.   Chroma is the technique of removing a certain color from the video…so for example, if there is a GREEN screen, and you stand in front of it wearing a color that isn’t green, a computer program will CHROMA out the color green and replace it with anything.  A mountain background, a weather forecast, or a giant lizard attacking the city. 

They also use a computer program to create a digital map of the playing field, they arrive hours before the game and lay a set of “digital” lines over the real field using specialized cameras and software. 

Instead of me going into mundane details, luckily we have YouTube.  Thanks YouTube. 

And now you know.  And I know.  And we can all sleep at night.