If its a cleaning advertisement, house cleaning, laundry or some terrible stomach problem – then the ‘actresses’ used have dark hair and brown eyes.
However, if it’s a beauty product, for hair, for skin, for shaving (showing lots of skin) – then the girl (usually VERY young) has dark hair and blue eyes.
I’ve spoken to a few people about it. They say that after Franco, the media turned its gaze upon the daring Scandinavians, in particular the free and frivolous Swedes. The beauty ideal was blonde and blue eyed and preferably naked.