to dyeing

I've been dyeing my hair for the last three years.

Je me teins les cheveux depuis trois ans.

I'm dyeing my hair black.

Je me teins les cheveux en noir.

Mary has been dyeing her hair for years.

Mary se teint les cheveux depuis des années.

This is what you'll wear when I finish dyeing it.

C’est ce que tu porteras quand j’aurai fini de le teindre.

— Harry Potter and the Philosopher's Stone (2001)