CBS 2's morning team has St. Patrick's Day fun with green garments and chroma key
CHICAGO (CBS) -- Many donned green apparel Friday in celebration of an early St. Patrick's Day – but in the TV news industry, wearing green has some longstanding pitfalls.
Chroma key, or green screen, technology has roots that date back well over a century – and has been in use in television news for generations. It involves graphics, photos, or video being superimposed over a solid green screen.
This, of course, is the technology that makes it appear that meteorologists are standing in front of a series of weather graphics that take up your entire TV screen.
But wearing green on a chroma key screen will cause trouble. If someone is wearing a solid green garment, the graphics and images will be superimposed over them right along with the screen – resulting what will appear to be a disembodied floating head and hands.
Even wearing an item with a hint of green will be disruptive.
While weather forecasts are likely the best-known use of chroma key in TV news, the technology was also at one time used to superimpose relevant images or graphics behind anchors as they read stories. At one time many years ago at CBS 2, Walter Jacobson ran into a problem when the screen was behind him – as it seemed to viewers that his favorite blue and green tie that he'd purchased in Ireland that past summer was suddenly changing colors and patterns.
In the clip below from a 1978 Channel 2 newscast, Jacobson has a basic explanation of chroma key technology – and why he could no longer wear his favorite tie. Meteorologist Harry Volkman appears briefly at the end.
But lo these more than 45 years later, Dana Kozlov – clad in a green dress this Friday before St. Patrick's Day – took full advantage of the chroma key screen, much to Brad Edwards' and Laura Bannon's amusement as seen in the video at the top of this story.
On Saturday morning at 10 a.m., the Chicago River will be dyed a shade of green similar to a chroma key screen, in a beloved St. Patrick's Day tradition that dates back to 1962.