Brassiness occurs when a hair color, usually a high lift color, does not lighten all the way to the desired color, and as a result, turns the hair a orange-like shade, the result of the natural underlying tones of dark hair (usually orange or red). Brassiness can also happen when hair color has not been touched up, and it oxidizes from a neutral, ash, or golden color, into a reddish-orange tone.

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