How much developer to use when dying hair?

How much developer do you use when using loreal hicolor for dark hair? The color is h16 honey blonde and the creme is 30 vol.
Thanx

use equal parts. If you use 4 ounces, use 4 ounces of developer.

I usee 2 bottles for my dark hair . now I have red

every1 is different, I would go to a sally suppy store and ask them.

The general rule with color and toners is a ratio of 1:2 - meaning if your bottle of color says 1.5 oz then use 3 oz of developer - if your bottle says 2 oz then use 4 oz of developer - keep in mind what your total ounce-age will be - if you have long hair and you get one bottle of color you will only have 4.5 oz of mixed formula - and you want to make sure to get even coverage so you'd probably want two bottle of color - for medium to long hair you want at least 7 oz of mixed color

Use equal amounts of both color and developer. The reason your hair turned red is because of the undertone to your hair being red and the the haircolor having a red base. Trust me, I know from experience. You will need to lift your hair color (40 developer) and then deposit color with a lower (10) creme developer. Sally's or a hairdresser should be able to recommend a lifting agent to use with the 40 developer. The color you deposit should not have a red base because that's what your naturally dark hair is going to pick up most. You will need to use a blue base color.

I have the loreal excellence color 4.4 dark auburn. it has an orange base. I am using a 40 volume developer, if I mixed 2 oz of color and 40z of developer would that be correct?
thank you

what will happen if you add more developer than directed to the hair color?