Sorry -- I overlooked this question you asked me.
Liquid Peroxide is used to bleach hair, hence the term `` Bottle-blonde``.
However, [ note the spelling] ` Creme Peroxide` is literally a thick-ish cream , but it still has enough of a viscosity to allow it to ` flow`..... it has a percentage [usually 9 or 12 %] of Peroxide in it...this acts as a catalyst when mixing it with colouring paste, such as Koleston perfect, in order for the colour to ` develop`.
The fact that it is not ` pure`[100%] peroxide means it will not bleach the hair if applied to it..it will have a ` lightening` effect on any colour which has been applied to the hair, so if you went a tadd too dark, by leaving colour mix on too long, you can use it`s [relatively mild] ` bleaching` qualities to lighten the colour again.

I'll just add to the above by saying that creme peroxide (also known as developer) is the active agent in the dying process and prepares the hair to accept the dye. ie, strips the hair & makes it porous.
The percentage of the peroxide indicates its strength.

If you're just changing your hair colour to a few shades darker, then you only need a 4% or 6%.
Dramatic changes can mean using a higher strength right up to 12%.
Most off-the-shelf home dyes have a 12%.
Because replacement hair has already been process & stripped & dyed, it is much more susceptible to absorbing colour than your own natural hair would be, it will dye faster & deeper.

Like Paul, I dye my hair using tubes of professional hairdressing dyes.
I use the same colour on my replacement & natural hair.
But I mix up 2 batches.
The replacement hair has a 2% creme peroxide developer & 12% for my own hair.

Because different lighting brings out different tones in hair, I really wouldn't recommend store bought dyes. They often have brassy tints in them where as the professional dyes have a much wider range of colours & more subtle shades.

You can buy them on-line or from places like Sally's, worldwide.

I'm only referring to percentages above.
For details & info re Vols (seen on creme peroxide bottles) read:
http://www.using-hydrogen-peroxide.com/h...oxide.html


I hope this info helps someone.

Hersute wrote: "The replacement hair has a 6% creme peroxide developer & 20% for my own hair."

This is quite genius! When I color a new piece I use the same mix on its hair and my own and all is well. But when I come to recolor it a month down the line the piece hair colors faster than my own so I try to time it by applying to my own first, then the piece, but often the two don't come out 100% perfect. This idea of yours has got my interest.

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Hersute - what are those percentaages equivalent to in vol numbers such as 10,20,30,40? The bottles I get are 10 vol. I have used 40 in the past for bleaching.

I've just checked my peroxide and the stuff I use on my piece is actually 2% Vol.7, so I've edited the post above & changed it.

I found this which sort of helps answer your question re Vols.
Though having read it and learned that 'VOL' refers to Oxygen levels, I'm a bit confused myself!

All I know is that I use lowest possible % on my piece and a middle to high % on my natural hair.

LINK:
http://www.using-hydrogen-peroxide.com/h...oxide.html

Thanks Hersute! Vol 10 is working great for my piece and I will probably try a 20 for my own hair next time.

By the way, off topic here I know, but how did you get on with the 4 layers of ORWG approach? Did it solve the problem or did it just give you a Freddy Kruger clean up session?

The 4 layers at the front lasted about 8 days with no touch ups.
So I recommend it and will doing that as standard from now on.