Basic color question

[uniq12u]

When coloring hair does it matter:

1. how much product you put on the hair?
2. the developer has sat around for awhile? Does the strength of it deminish over a short period of time?
3. is it the amount of product you put on the hair, or the amount of time the product is on the hair that determines the degree of color?

The reason I'm asking is because someone I know likes her hair not quite platinum, but not a yellow blonde either. Trying to find out for her why it has been coming out more yellow. She is using a 40 developer with her color. It was coming out plantinum and now it's coming out more yellow. She is wondering why?

 

[-sophisticutz-]

Yes to all of them. If there is not enough product on the hair it will develop patchy. If you don't leave the development to the required time the colour will not have time to deposit, with blondes it won't lift high enough giving a brassy shade.
Peroxide has a shelf life of 1 year once opened but actually does start to lose it's 'potency' from the first opening. I personally wouldn't use any beyond 6 months. However, if it's in a busy salon I doubt very much they would have any that old. I go through roughly 3, litre bottles, per week.

 

[kimi1101]

I say with developer...its like fizzy juice. Its at its fizzyest when you first take the lid off, and if you leave the lid off it will go completely flat. Thats the easiest way I found to remember, cos you really should put the lid back on developer as soon as you've used it. xx

 

[minky]

When coloring hair does it matter:

1. how much product you put on the hair?
2. the developer has sat around for awhile? Does the strength of it deminish over a short period of time?
3. is it the amount of product you put on the hair, or the amount of time the product is on the hair that determines the degree of color?

The reason I'm asking is because someone I know likes her hair not quite platinum, but not a yellow blonde either. Trying to find out for her why it has been coming out more yellow. She is using a 40 developer with her color. It was coming out plantinum and now it's coming out more yellow. She is wondering why?

Hi uniq12u , is the person doing her hair colour a fully experienced hairdresser ? or is he /she just training ?

 

[uniq12u]

TY for the replies. I will let my friend know. Sorry for replying so late. I was w/o a computer for a few days. Glad to be back!!