Hair colour has evolved far beyond a simple beauty ritual — it’s now a global art form that reflects culture, personality, and innovation. From classic highlights in Paris to vibrant avant-garde hues in Tokyo and personalized colour blending in New York, global hair colour services offer unmatched creativity and individual expression. This complete guide explores the world of professional colour services, from key techniques and trends to considerations for choosing the right service, ensuring healthy hair, and navigating cultural preferences.