Hair dyeing; the act of changing the color of one's hair or the process/products used to do so.
学校の規則で学生の染髪は禁止されているところもある。
Some schools prohibit students from dyeing their hair.
彼女は週末に美容院で染髪して、髪色を明るくした。
She had her hair dyed at the salon over the weekend and brightened her color.
敏感肌の人は染髪剤で頭皮がかぶれないか注意が必要だ。
People with sensitive skin need to be careful that hair dye doesn't irritate their scalp.