'This season black and white is trying to be fun and to do that it has to subvert expectations'
The meaning of black and white should be clear. Isn't that what is intended by the phrase "in black and white", after all? Black-and-white clothing is an age-old signal of servitude and humility: think of a priest's robes as contrast to papal raiments, or a waiter's uniform in a smart restaurant as a counterpoint to the finery of the female guests.
It's not quite as simple as that, though. The uniform of a waiter and a man in a classic black-tie tux signify different things. And more than half a century ago the meaning of black as a colour evolved from melancholy of a fundamental nature (funerals) to include boredom as an affectation or lifestyle choice. Certain pieces of black and white clothing retain their meaning – a white dress for a bride is a tradition that shows no sign of shifting – while on a more muted level black jeans have somehow retained an air of rock'n'roll cool that no longer applies to blue jeans. But the sands shift.
One constant is that black and white means serious. This is why birth announcements come with a black-and-white photo of the newborn (also, babies can look blotchy, so monochrome or sepia are flattering in this respect). Conversely, breezy holiday snaps will be posted on Facebook in Technicolor (or the modern equivalent: X Pro II or Kelvin). A man in black tie is dressed to play the straight guy to a more gaudily dressed date.
But, this season, black and white is trying to be fun, and to do that it has to subvert expectations. The boldest route is to embrace Op Art stripes, chessboard graphics or mixed monochrome prints. This isn't a look for wallflowers: an outfit that is black and white yet gaudy in its pattern sends contradictory messages, so if having strangers staring at your outfit in a puzzled fashion is going to freak you out, avoid. (As someone who has strangers staring at my outfit in a puzzled fashion every Saturday, I crashed through that pain barrier a while ago.) You can bend the rules without giving the world a headache – a black trouser suit with a white stiletto, say, turns the landscape of a business suit (black suit and shoes, white shirt) upside down. Black and white: simple has never been so complicated.
• Jess wears blouse, £195, mywardrobe.com. Trousers, £185, by Kate Spade,020-7836 3988. Heels, £45, asos.com.
Photograph: David Newby for the Guardian. SHair and makeup: Dani Richardson using YSL Beauté.