Thousands of conventional television sets were being nudged towards obsolescence yesterday with the move by RTÉ News to a widescreen format.
As a result, viewers with old-style sets will see thin black bands at the top and bottom of their screens when viewing the station's news bulletins, according to a spokeswoman.
However, she said, there will be no stretching or other distortion of images.
Conventional televisions have an aspect ratio (width of screen to length of screen) of 4:3, whereas widescreen television sets provide an aspect ratio of 16:9.
The promoters of widescreen say the format delivers a picture which is closer to how the natural eye sees the world than conventional television.
Sales of widescreen televisions have mushroomed in recent years as prices have fallen, but tens of thousands of viewers still rely on conventional sets. Conventional 4:3 televisions are difficult if not impossible to buy now.
To coincide with its switch to the widescreen format RTÉ News yesterday unveiled a new-look set, lighting and graphics. The spokeswoman described the new set as "a composition in walnut, glass and aluminium".
"The feel is of a room, with real materials and textures, rather than a studio set, creating a mood of warmth, strength and authority."
TG4 also moved to widescreen yesterday, while other RTÉ programmes switched to the format last year.
The spokeswoman said her advice to viewers who notice their news pictures have changed is "do not adjust your set".