I'd be very grateful if anyone can advise!
I have been using a no 11N hi-lift tint all over my naturally blonde hair for the past few months (I used to have a regular full head of highlights but the regrowth was dreadful and I was spending a fortune).
I normally use a 30 vol developer with the hi-lift, and leave it on for 45 mins. The result is OK but a bit ginger. My hair is in good condition.
Should I use a 40 vol developer, and leave it on as long? I thought that should lift it slightly more.
Any advice appreciated!