Global base colour works across the hair rather than isolated sections. It can establish an overall shade or refresh a colour that has become uneven.
Your starting shade, earlier colour and the condition of the lengths all affect what is practical. Bring a reference in natural light. A substantial change may need a different plan from a simple refresh, so discuss the route, maintenance and testing with the colourist before proceeding.
The target shade, previous dye or lightening, upkeep and allergy testing.
AI-generated treatment illustration.