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Colour theory

Colour theory is the set of rules describing how colours relate to one another and why some flatter a given skin while others do not. Applied to nails, it is what makes it possible to choose a shade that sits in harmony with the hand rather than competing with it.

What three things define a colour?

Any colour can be described with three variables, and mixing them up causes most wrong choices. Hue is the family: red, blue, green. Saturation is how much of that hue is present, from a neutral grey to a full colour. Lightness is how much light it carries, from near-black to near-white. Two polishes can share a hue and look nothing alike because one is muted and the other is not.

How does the colour wheel work?

It arranges hues in a circle, with the primaries spaced out and their mixtures between them. It supports two concrete decisions. Colours facing each other across the circle, such as red and green or blue and orange, produce maximum contrast: they reinforce one another and draw the eye. Neighbouring colours, such as coral, red and burgundy, share a base and produce harmony: they blend and the result reads calm.

Why does skin come first?

Because a nail is never seen on its own. It is seen on a hand, and the eye compares. What decides whether a shade looks clean or muddy is not the colour in the bottle but how it relates to the undertone of the skin around it. A cool-undertoned skin and an orange-based red push against each other and the whole thing loses definition; that same skin with a blue-based red reads as deliberate.

How is the choice made in practice?

Work from general to specific. Identify the undertone first, since that is the part that does not change. Decide the intention next: to disappear, to accompany, or to stand out. Only then pick the hue, and adjust intensity last, because intensity is the variable that fixes almost everything. A shade that looked like too much usually works perfectly two steps down in saturation.

Are there colours that do not suit people?

Not in the sense of being forbidden. Some simply demand more precision than others. Shades very close to skin colour require the undertone to be read fairly accurately, because an error there reads as a tired-looking hand. Highly saturated shades are far more forgiving, because the contrast is so high that comparison with the skin stops being the point. Length matters too: the same colour reads as more intense the more surface it occupies.

What about season and occasion?

They are useful shortcuts, not rules. Associating warm bright shades with summer and deep muted ones with winter has to do with ambient light and with the clothes alongside them, not with any law of colour. The same goes for occasion: a matte finish mutes any colour and makes it discreet, while the identical hue in high gloss steps forward and asks to be noticed.

Sources: Regulation (EC) 1223/2009 on cosmetic products (EUR-Lex) · AEMPS · Cosmetic products (Spanish Medicines Agency)

Published: 12 October 2026 · Last reviewed: 12 October 2026