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Everything you need to know about Developer

Published on 20th May 2018

Developer, peroxide, hydrogen peroxide, oxidant; when it comes to hair dye it’s all the same thing, and it’s a key ingredient in many hair colours and bleaches. This article addresses common questions to help you understand how to use developer.

What’s the difference between 10 volume, 20 volume, 6%, 9% peroxide?

Developer comes in different strengths, the common ones being 10 volume, 20 volume, 30 volume and 40 volume. It’s possible to buy peroxide in stronger concentrations but they’re much too strong to use on hair and should be avoided. Developer strength is sometimes represented as a percentage. 6% and 20 vol. are the same strength.

Equivalent Developer Strengths
10 Volume 3%
20 Volume 6%
30 Volume 9%
40 Volume 12%

Read on to find out how to dilute peroxide to a lower concentration.

What strength/volume developer should I use?

10 volume is ideal for use when you don’t want the natural hair colour to be lightened by the dyeing process. It’s used in toners and colour glazes. These types of dyes are known as “deposit-only”.

20 volume peroxide is commonly used with semi-permanent and permanent hair colours. Boxed hair colour that you buy in the grocery store usually comes with 20 volume peroxide. It can have a lightening effect on natural, undyed hair of 1 or 2 shades when used with permanent colour.
When mixed with bleach powder, 20 volume developer will lighten virgin hair by about 5 levels. (Follow this link to learn more about hair colour levels).

30 volume developer is used for lifting out colour. Its main use is in bleaching and it can lighten around 7 levels depending on the bleach powder used.

40 volume is occasionally used to lighten very dark, stubborn hair as part of the bleaching process. It lightens quickly and its effects are harsher than lower concentrations. 40 volume is not recommended for on-the-scalp use. Using 40 volume developer can cause hair damage and chemical burns if not used correctly. Instead, using multiple applications using lower volume peroxide will allow more controlled lightening.

How can I dilute peroxide?

While it’s better to buy the correct strength of peroxide, it is possible to dilute it slightly to reduce the concentration. Don’t dilute it too much or you’ll ruin the consistency.

Diluting Peroxide with water
Dilution Mixing Ratio
40 volume (12%) to 30 Volume (9%) 3 parts 40 volume peroxide : 1 part water
40 Volume (12%) to 20 Volume (6%) 1 part 40 volume peroxide : 1 part water
30 Volume (9%) to 20 Volume (6%) 2 parts 30 volume peroxide : 1 part water
20 Volume (6%) to 10 Volume (3%) 1 part 20 volume peroxide : 1 part water

Distilled water is better if you have it, but tap water will do.

How much peroxide should I mix with bleach powder?

A typical ratio is 1 part powder to 2 parts developer and works well for all lightening techniques. Mix 30g of powder bleach with 60ml of creme peroxide. You can also use a 1:1 or 1:3 ratio. A 1:1 ratio of bleach powder and peroxide will make a thick mixture that works well for highlights and balayage, especially if you intend to keep your hair uncovered while it processes. 1:3 ratio is good for on the scalp lightening, (e.g. root touch up) and its thinner consistency makes it easier to apply, though you may notice more slippage.

Read more about bleaching your hair.

Does developer go bad? How long can I keep developer?

Most creme peroxides should be used or discarded within 12 months of opening. Check the bottle for the Period After Opening symbol (a small jar with an open lid). The number stated there will probably be 12M or 24M – 12 or 24 months. Developer does go bad and loses effectiveness over time.

To get the most from your developer, always replace the lid and store it away from sunlight in a cool place. Do not store it in a warm environment.

If you’ve mixed your developer with colour or bleach then it cannot be stored and should be disposed of safely.

What’s the best brand of developer use?

Some brands of bleach will specify that you use the matching brand of developer, but generally it’s fine to use a generic store brand peroxide which is much cheaper. Save your money and buy the best bleach or dye you can afford since there’s very little difference between cheap and expensive developers.
The most common kind is creme (cream) peroxide but there’s also liquid peroxide which is clear instead of creamy. Creme peroxide is easier to use because it creates a better consistency when mixed with dye or bleach.

Can I use household bleach to lighten my hair?

No! Not only is this ineffective, it’s dangerous! We see people asking “how to bleach hair with Clorox” and the answer is, just don’t! Putting household bleach on your hair is a terrible idea. It won’t lighten your hair but it may burn your skin, damage your lungs and affect your vision. Always use proper hair bleach to lighten your hair and follow the manufacturer’s instructions.

Can I use hydrogen peroxide to lighten my hair?

Peroxide on its own won’t do much to lighten your hair. If you apply a moderate strength peroxide to your hair (e.g. 20 or 30 vol.) then you’ll see a slight lightening of your natural hair colour over time but for noticeable results you need bleach or dye to boost its lightening power. Using bleach powder and peroxide is the fastest and most effective way to lighten your hair.

Does developer damage hair?

On its own, not really. Developer applied directly to your hair hasn’t got much to activate it so it barely lightens and doesn’t do much damage without something else to activate it. So in scenarios where you need to apply developer directly, like pre-softening your hair or checking whether a colour remover has worked, there will be no noticeable damage.
Peroxide can cause damage in combination with bleach powder or dye, but developer itself isn’t particularly damaging.

Can I dilute developer with conditioner?

It’s better to use water to dilute developer (see the table above for ratios). The water content of conditioner varies a lot from one brand to another, which makes it impossible to accurately judge how diluted the developer is.

Can I use developer on damaged hair?

This depends on what the developer is being mixed with. If you’re applying it on its own, then anything up to 30 volume developer is usually fine. There are few cases where you would need to apply developer on its own though.
If you’re toning blonde hair then it’s usually fine to use 10 volume developer with the appropriate dye. If you’re lightening your hair with bleach or dye then you’ll need to use 20 or 30 volume developer. Any lightening process will damage your hair. Do a strand test before applying any new product to your hair to check the outcome.

Was your developer question covered? If not, let me know in the comments.

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