Red is carrying the season. Reformation's Bryson dress and Tove's Eilis sweater are the flat, saturated version, while Frame's suede shirt and the Sanderlak corduroy trousers take the same shade into heavier cloth. Galvan's satin blazer is the one that shifts with the light.

The Sanderlak corduroy trouser is the easiest red to live with because the pile absorbs light. The Tove Eilis ribbed sweater is brighter and works as the single red piece in an outfit.

The Gucci perforated sweater lets the shirt underneath show through, which changes the red. The Frame panelled suede shirt is the deepest red here and reads almost brown indoors.

The Galvan satin blazer is the loudest red of the group and needs everything else kept flat. The Khaite Kelly cashmere sweater is the version you can wear on a Tuesday.

Cobalt has to be genuinely bright or the pairing collapses. Pleats Please Issey Miyake's July blouse and the Polo Ralph Lauren cable cardigan hold the strongest blue here, and Bode's embroidered corduroy and Rier's wool fleece dress keep it matte. Theory's pleated skirt and Posse's broderie dress are the softer entry.

The Theory pleated midi is the cobalt that moves, and the pleats break the colour into lighter and darker lines. The Posse Veda keeps it flat and lets the cutwork add texture.

The Bode Stagecoach trouser is the statement half, with embroidery running through the corduroy. The Auralee cardigan has the uneven blue that comes from dyeing after knitting.

The Rier wool fleece midi is the daytime cobalt, warm and matte. The Zimmermann Aster is the night version, beaded over silk satin and catching every light in the room.

Accessories are where most people start. The bags and shoes in this last group are all red, which is the easier of the two colours to wear near your face or not at all. A red mule or a red shoulder bag gives you the whole story with one item, and the blue can stay in the clothes.

The Le Monde Beryl Luna ballet flat is the quietest red shoe here and goes with a jean. The Manolo Blahnik Pirua 70 ruches the suede, so the colour shifts across the foot.

The Roger Vivier Viv In The City at 85mm keeps the buckle at the toe. The Saint Laurent Cassandre clutch in glossed leather is the brighter red of the two.

The Givenchy Pinch clutch is soft and folds around whatever you put in it. The Alaia Le Teckel is long and structured, which makes it the more formal option.

If you take one thing away, it is that this pairing needs both colours at full strength. Muted red with dusty blue reads as an accident, while true scarlet against true cobalt reads as a decision, and the gap between those two outcomes is entirely about saturation. Keep the rest of the outfit out of the way. No print, no third colour, and preferably nothing metallic. If wearing both at once feels like too much, start with red from the waist down and a blue knit on top, since that split is the least demanding version. The accessories group here is the low commitment route and will still get the idea across. Denim does not count as the blue half, however tempting that shortcut is.