Colour help please

[Fififlower]

My neighbour has a lot of warmth in her hair and wants to get to a very light ash blonde. She has a lot of orangey tones going on. I have xp100 12.21 special blonde violet ash that I was going to use but the question I have is if I take her too light with the bleach will her hair end up with a lavender tone? Would I be better just using an 11.0 in the same range or the 11.0 with a small amount of the 12.21 ?

 

[AcidPerm]

Please post using technical terms. What’s your base?

 

[Fififlower]

Her natural base is about a 6, not sure about the mid lengths and ends as she used a box colour and can't remember but looks to be about an 8

 

[AcidPerm]

If she’s got box colour on, you’ll have to remove that first then bleach the remainder but you’ll need to be careful not to leave it patchy looking.
You’re not supposed to use highlift tints to tone bleached hair as there isn’t enough colour pigment in them to tone, so choose your toner to match the level you’ve lifted to.