"Smoky steel" is a gray hair coloring technique that combines dark, ashy tones with cool silver rather than applying a single flat gray shade. Adam Russell, creative master colorist at Josh Wood, told Harper's Bazaar that adding subtle beige, taupe or mink warmth into gray creates a more luminous, diffused look against the skin, and that the warmer tones blend more seamlessly as natural gray grows in.
The technique has been seen on Andie MacDowell and Olivia Colman and works across long curls, a sleek bob or a topknot, according to the outlet. Russell said balancing warm and cool pigments in the color keeps it from reading as yellow or brassy, and that a colorist can further soften the look by blending highlights between the roots and ends.