The rings must never be shown in Olympic yellow on a white background, because yellow does not contrast enough against a white background.

FORBES: Olympic Hurdles For Advertisers: The Games' Unique Rules And Restrictions

In contrast, gainst a background of inflated expectations, Samsung needs five big wins today, five headlines that will draw people into the showrooms.

FORBES: Tim Cook Will Sigh With Relief Following the S4 Launch Today

Beyond the sleek design and processing power, VIZIO continues to leverage its HDTV background with brilliant picture quality, high contrast and wider viewing angles, a staple of the Touch PCs.

ENGADGET: Vizio brings pricing and release information to spring line of laptops and desktops

Mr. Santorum espouses an economic nationalism and highlights his steel-town Pennsylvania heritage as a contrast to Mr. Romney's background as son of an auto-company chief executive.

WSJ: On the Road With Rick Santorum as He Takes Spotlight, Tests GOP

The tunnel is brightly coloured to optimise the contrast between the subject's clothing and background, making it easier for the researchers to capture a 3D image as they walk.

BBC: Biometrics cybersecurity research gets government cash

It is part of his efforts to contrast his own blue-collar roots with Romney's personal wealth and Wall Street background.

CNN: Santorum benefits from staying in GOP race