Double Developer!

[Vickyzoki]

Hi I am training in hairdressing and my mind is always ticking over with questions even when I'm trying to sleep which I cannot always find the answers to in text books or on the net. And I am to impatient to wait until I speak to my tutor!
My question is a mixing ratio question. If I mix say 60 ml colour with 120 ml of 20 vol/6% developer does that then double the strength of the developer to 40 vol in this mix or is it still 20 vol. if so then can someone explain the 'science ' behind it and what is the reason for this Mixing ratio?

Thank you

 

[gin_ja_ninja]

It keeps it the same strength just dilutes the colour it's like with high lift some are 10g tint to 20g 40vol doesn't make it 80 vol but one thing I learned is resistant mix with any color makes it stronger that why it covers red more and I've asked many hairdressers I've worked with the tone is a lot stronger and with high lift mixing 1 to 1 gives stronger lift with more tone so doesn't throw as much warmth but its not recommended but then again it doesn't say you can't

 

[vixxm]

20vol will always be 20 vol no matter how much you have in your bowl, if you add 10 mls of 20 vol with 10 mls of 20vol you don't get 40 vol, In the scenario you are talking about you just have a higher ratio of peroxide to tint, so it would lift the hair more but leave less depth, double H2O2 is only used in high lift tint and only when more than 4 shades of lift are required ,so its not making it stronger but increasing the amount of H2O2 in your mixture

 

[adamlea87]

Hi the actual final strength of your developer is called the 'working volume'.
When you mix the peroxide with the colour cream you dilute the strength of the peroxide, so for example:

50ml Colour
50ml 20vol (50 x 20 = 1000)

Total Volume = 100ml (1000/100 = 10vol)

In the example above the colour is mixed in equal parts therefore diluting the 20 vol down into 10 vol


If you were to mix in a 2:1 ratio:

50ml Colour
100ml 40vol (100 x 40 = 4000)

Total Volume = 150ml (4000/150 = 26vol)

In the example above mixing double amounts of 40 vol with say a highlift tint will give you a working volume of 26 vol.


Peroxide is stored at an acidic pH to keep it stable, whereas your colour is alkaline, so when you start changing the ratio of developer to colour you also change the pH of the product, which will obviously change how the product performs.
A high lift tint can afford to use so much developer since the colour is more alkaline.

 

[Vickyzoki]

Thanks everyone for your responses this has helped me a lot!