Collect as much information as possible about the hair dye you are going to use because they differ a lot in mixing ratio and the lightening effect of oxidizer.
I do recommend the following hair dyes: Wella, Revlon, Matrix, L’oréal, Swarzkopf , they are the bests on the market.
Before dyeing your hair, you must know a few things about your hair, like the absorbency of your
Vol. 20 – dye to same colour, darken, dye to one shade lighter
Vol. 30 – dye to 2-3 shades lighter
Vol. 40 – dye to 3-4 shades lighter
When you dye your hair roots to a lighter colour, the pigments in your hair change colour to reddish, yellowish. You can offset this by using ash-blonde, more matt colours.
We call lifeless and dry hair ends matt or green. To avoid it, mix red, copper or gold mixton in the colour.
I have written only colouring because never should you dye the whole length and the ends of your already dyed hair just refresh the colour by colouring (temporary hair colour).
Let me explain:
Natural hair colour is no. 7 blonde (hair roots)
The colour of the whole hair is no. 8 light blonde, dry, matt.
Desired hair colour is no. 8 natural light blonde without gold undertone.
Hair dye plan
8/ ash -shade hair dye. You will need this to offset the orange pigments and end up with the desired natural colour. Use vol. 20 oxidizer to lighten one shade.
Length of hair and hair ends:
Refresh your colour by using no. 9 hair colour + red mixton colour (don’t use no.8 light blonde, because it may result in over pigmentation and the length of your hair is not faded but only dull). Add 1 unit:
hair colour + 2 cm
red mixton + 2 units of developer.
You can make you hair shiny by doing this and don’t be afraid, it won’t get red. (always go for a shade lighter colour to refresh original colour if not faded)
If you dyed your hair with colour no. 8 light blonde than your hair roots would have a shiny gold undertone and the rest of your hair and hair ends would become darker thanks to the absorbency and dryness of your hair. It would be more matt too and could end up with a greenish undertone.