Warm
undertone

How to recognise it

In daylight, on bare skin, with your hair tied back. Undertone is a colour, so it can only be read where there is honest light and nothing else competing for it.

• — Gold held against your jaw lifts the face. Silver looks flat or slightly grey beside it.
• — Against a sheet of plain white paper, the skin reads yellow, golden or peach rather than pink.
• — The veins at your wrist look green rather than blue, though this test is the weakest of the three.
• — Foundations you have bought that turned out grey, ashy or chalky on you were almost certainly cool shades on warm skin.
• — A cream or off-white shirt suits you better than a pure optic white one.

Measure it rather than guess

Every one of those tests asks your eye to judge a colour against whatever else is in the room, which is the one thing eyes are reliably bad at. The undertone finder reads the colour of two patches of your cheek from a photograph and places it on the yellow-to-blue axis directly. It runs in your browser, it is free, and nothing is uploaded.

Foundation

Look for the words golden, warm, honey, caramel, sand or beige-gold, or a shade code ending in W. Avoid the ones named rose, porcelain, cool or beige-rosé: those are the shades that go grey on warm skin within the hour. Where a range offers the same depth in two temperatures, take the warmer of the two.

Test along the jaw and down onto the neck, never on the back of the hand, and leave it twenty minutes before deciding. Most formulas oxidise slightly warmer and deeper as they meet the oil on the skin, which warm skin tolerates better than any other undertone — but a shade that already looks orange in the bottle will only look more so. If it reads orange after settling, the base is too red rather than too yellow, and a yellow-based shade at the same depth will sit better.

Under the eye, a concealer half a shade lighter with a peach or apricot base cancels the blue-grey shadow that warm skin tends to show there. A concealer that is merely lighter, with no warmth in it, lifts the area and leaves the grey.

Blush, bronzer and lips

Coral, peach, apricot, warm terracotta and brick all read as though the colour came from underneath rather than out of a pan. Bronzer with a golden or neutral-brown base works; anything with a grey cast in it looks like dirt on warm skin. For lips, tomato and brick reds, warm rose, and nudes with caramel or honey in them.

Cool blue-pinks and icy mauves are the colours that fight hardest, and they can read bruised against a golden cast. That is worth knowing rather than obeying: a cool pink on warm skin is a deliberate contrast, and if you like the effect it is not a mistake. The rule only tells you which colours need no help.

Metals

Yellow gold is the obvious one, and brass, bronze and rose gold all behave the same way. Copper and antique gold sit especially well. Bright polished silver does least for warm skin, though brushed or oxidised silver, which has warmth in its grey, is easier to wear. For eyes, bronze, copper, warm brown and olive shadows lean on the undertone rather than working against it.

What is a myth

That warm means tanned, deep or olive. Depth and undertone are two separate axes: very fair skin is frequently warm, and deep skin is frequently cool. Choosing a foundation on the assumption that the deeper shades in a range are the warmer ones is how people end up a full step off in both directions at once.

Two smaller ones. Self-tanner does not change your undertone; it changes your depth, and the cast underneath stays where it was, which is why a self-tanned face often needs a deeper shade of the same temperature rather than a warmer one. And warm skin is not barred from silver. The metal simply does less of the work for you, which is a different claim entirely.