When Sir Isaac Newton arranged the colours of the rainbow into a circular colour wheel for the first time in his seminal work in 1704, he couldn’t have known the extent to which it would be adopted in the 322 years since. Colour theory has infiltrated all aspects of artistic expression, from art to interiors and, more recently, cosmetics.

An idea that has gone stratospheric on TikTok, colour theory in make-up is most commonly considered in the realm of colour correction: the strategic use of colour on the opposite side of the wheel to balance out discolouration, redness, hyperpigmentation or neutralise bluish-purple tones. Under-painted before foundation, colour correcting concealers are hugely popular in Korea and have found their way onto UK soil. Take dark circles, for instance. When this occurs, you can select a pigment with a peach-orange hue, then call on green when it comes to neutralising redness. When your skin is looking dull, on the other hand, look to purple or yellow shades.

This concept goes beyond concealer and can be applied to blush shade selection, too. When choosing the hue to best suit your skin tone, like with foundation, undertone comes into play. Ilia’s executive director of global education, Sam Michalska, explains, “Blush colour theory takes the fundamentals of colour theory (undertone, saturation and value) and applies them to blush selection and placement. The goal is harmony: a shade that works with your skin’s undertone and depth so it reads as a natural flush, or one that’s intentionally placed to lift and sculpt the face.”

This is something that Sofia Tilbury, global artistry director at Charlotte Tilbury Beauty, pays close attention to: “For me, blush colour theory is about finding a shade that brings your complexion to life in the most flattering way. As a make-up artist, I look at the depth and undertone of someone’s skin – you could have a fair, medium, tan or deep complexion with a cool, neutral, warm or olive undertone.” She then considers the effect her client is looking for: “It could be a subtle, natural flush or a more playful pop of colour.” And lastly, it’s a question of placement. “A soft rose swept across the cheeks can feel romantic, while the same shade placed higher on the cheekbones can look fresh and lifted. It’s about understanding how colour works with your unique features, rather than following a strict rule.”

Yet there are some general guidelines that you can follow, which vary according to whether you want a fresh, radiant complexion, a natural no-make-up make-up look or a pop of colour that stands out. “If you’re after a natural flush, match your blush to your undertone: cool skin tones look beautiful in cool, rosy blushes, while warm skin tones glow in peachy or coral shades. But make-up isn’t always about blending in! If you want your blush to stand out, try going the opposite way. A warm blush on cool skin can look bright, punchy and fun. From there, think about the depth of your skin. Deeper skin tones usually need more saturated, pigmented shades to really show up, while fairer skin tones do best with softer, sheerer colours that are easier to blend.”

A make-up artist trick is to use two shades: one lighter and one darker to bring dimension. “It’s one of my favourite artistry tricks,” Tilbury tells me. “I’ll start by diffusing a lighter shade across the cheeks and then use a deeper shade on the apples of the cheeks to intensify and make them pop. The trick is to blend them into one another, so you see a beautiful flush, rather than where one colour begins and the next ends.” This links to colour theory too. Michalska explains: “In colour theory, deeper shades recede and lighter shades come forward, so placing a darker blush along the cheekbone adds soft definition, while a lighter shade on the apples brings them forward and adds lift. I tend to think about neutral and bright rather than just light and dark.”

Don’t be intimidated by any blush shade, Tilbury stresses. “I’d say that the biggest mistake is deciding a blush isn’t for you before you’ve even tried it on your face! People can be intimidated by a bright pink or deep berry in the pan, but applied with a light hand and blended well, it can look completely different on the cheek. Equally, a very pale shade may need more depth to show up as a flush on a deeper complexion.” She also recommends shade-matching your make-up holistically. “If I’m creating a strong lip or eye, I’ll look at the blush alongside it so the whole face feels harmonious. Once you can see how your eyes and lips work together, apply less blush than you think you need before building. A little can go a long way. You can always add more.”

While high pigment is often what draws us to a blush, there are benefits of less pigmented blushes, say the experts. “For everyday, I love a layerable formula. I want to dip back into my blush a few times and really build the look, rather than getting boxed in by something so pigmented it’s hard to control,” says Michalska. Tilbury is a fan of the softer “anti-blush” trend that uses “a neutral, low-saturation blush that mimics your natural skin pigments,” putting equal weight on blendability. In terms of the latter, she prefers a formula that can be applied lightly to “build where I want more colour and blend into the rest of the complexion without a harsh edge. That’s especially important when I’m creating a look that’ll be photographed.”