Reviewed by the Tonebook color team · Updated June 2026
Your undertone is the subtle hue beneath your skin's surface, and it doesn't change with a tan. There are four: warm (golden/peach), cool (pink/blue/red), neutral (a balance), and olive (a green-grey cast that can sit over any depth). The fastest at-home checks: look at your wrist veins (green = warm, blue/purple = cool), and notice whether gold or silver jewelry flatters you more (gold = warm, silver = cool). Undertone is the first input of a full color-season analysis.
| Undertone | Looks like | Best metals | Tends toward |
|---|---|---|---|
| Warm | Golden, peach, yellow cast | Gold, bronze | Spring / Autumn |
| Cool | Pink, red, bluish cast | Silver, platinum | Summer / Winter |
| Neutral | Balanced, hard to place | Both work | any soft/true season |
| Olive | Subtle green-grey overlay | Muted gold | Soft Autumn / Summer, Deep |
Why the tests disagree. Undertone is one of three axes — undertone, value (how light/deep you are) and chroma (how bright/muted) — so two people with the same undertone can still be different seasons. At-home tests read undertone only; a full analysis reads all three together.
Rather than asking you to judge your own veins, Tonebook evaluates visible color cues from one clear selfie in neutral light and reports a warm, cool, neutral, or olive direction with confidence guidance before returning a 12-season result. It's designed to treat skin depth and undertone as separate signals, so the app reports confidence rather than claiming equal measured accuracy across skin depths.
Tonebook reads one selfie, places you in the 12-season system, and builds outfits in your colors — with confidence guidance when the result is close. The free preview includes your season and up to 10 colors.
Get Tonebook for iPhoneThat's exactly what 'neutral' means — a balance of warm and cool with neither dominating. Many people are neutral-leaning-warm or neutral-leaning-cool, which is why a single at-home test often feels inconclusive.
No. Your surface color (and Fitzpatrick type) can deepen with sun, but your underlying undertone stays the same. That's why color analysis is based on undertone, not tan.
Olive is a green-grey cast that can sit over fair, medium or deep skin. It's often misread as 'sallow' under bad lighting. Olive skin usually suits muted, slightly warm-neutral palettes and muted gold over bright silver.
It's a useful first signal but not definitive — skin thickness and lighting skew it. Pair it with the jewelry and white-paper tests, or run a selfie analysis that measures undertone directly.