What 10, 20, 30, And 40 Volume Developer Really Does

Hair developer is more than a liquid mixed with colour. Its peroxide strength controls how much the hair cuticle opens, whether natural pigment is lifted, and how deeply artificial colour can develop. Choosing the wrong volume can leave colour too dark, too warm, patchy, or unnecessarily dry.

So, what do 10, 20, 30, and 40 volume developers actually do? The answer depends on your starting shade, hair porosity, the colour formula, and whether your goal is deposit, grey coverage, or lightening. Australian heat, strong UV exposure, and dry ends can also affect how processed hair behaves.

How Hair Developer Works

Developer contains hydrogen peroxide, which activates permanent colour and bleach. As the volume increases, the peroxide concentration rises. This generally means greater lifting power, but it also increases the chance of swelling, dryness, breakage, and uneven results.

The numbers refer to the developer’s strength rather than the final colour level. Ten volume is gentle and mainly deposits colour, while 20 volume is commonly used for standard permanent colour and grey blending. Thirty and 40 volume are stronger options designed for controlled lightening, not routine all-over use.

What 10 Volume Developer Does

Ten volume developer is usually chosen when you want to deposit tone, refresh faded colour, darken the hair, or create a subtle change with a demi-permanent or permanent formula. It has little lifting ability, so it cannot reliably take dark brown hair to blonde.

It can be useful for glossing pre-lightened hair, deepening a blonde, or adding richness to porous lengths. However, porous hair may grab colour quickly, making the result appear darker than expected. A strand test is especially helpful when working with lightened or previously coloured hair.

When To Use 20 Volume

Twenty volume is the most versatile choice for many home colour services. It can lift some natural pigment while depositing artificial colour, making it suitable for permanent colour, root touch-ups, and many grey coverage formulas. The exact lift depends on the brand, shade family, application time, and your natural base.

It is often used for one to two levels of lift, although results vary. If your hair has existing artificial colour, 20 volume will not simply remove it; colour generally does not lift colour. For stubborn grey around the temples or hairline, thorough saturation and correct processing time matter as much as developer strength.

Thirty And 40 Volume For Lightening

Thirty volume can provide stronger lift with permanent colour or bleach. It is commonly used for highlights, balayage, and selected lightening services when the hair is in good condition. It processes more aggressively, so scalp sensitivity, previous chemical services, and hair porosity must be considered.

Forty volume is the most powerful of these common strengths. It may be used in professional high-lift colour or specific off-scalp lightening techniques, but it is a poor choice for casual experimentation. Higher peroxide does not guarantee a faster or cleaner result. For dark hair, follow a careful bleaching safety guide instead of trying to force dramatic lift in one session.

Match Developer Strength To Your Goal

The best volume is the lowest strength that can achieve the intended result. A professional in Melbourne or Sydney may select different formulas for the same shade because the client’s previous colour, texture, and condition are different. Hair history always matters more than the number printed on the bottle.

For a polished special-occasion appearance, hair colour is only part of the overall styling plan; a smooth seamless body shaper can also help clothing sit neatly while you show off a fresh colour service.

Common uses for each strength:

• 10 volume: Colour deposit, toning, refreshing faded lengths, and darkening
• 20 volume: Grey coverage, root colour, and modest lift with permanent colour
• 30 volume: Highlights, balayage, and stronger controlled lightening
• 40 volume: Limited professional high-lift or off-scalp applications

Avoid these common mistakes:

• Using 40 volume to compensate for an unsuitable shade
• Applying permanent colour over colour expecting major lightening
• Ignoring strand tests on porous, bleached, or chemically treated hair
• Leaving developer mixtures on longer than the manufacturer recommends

Protect Hair Before And After Colour

Australian conditions can make post-colour care especially important. Strong summer UV in Brisbane, Perth, or Adelaide can fade artificial pigment, while humidity may increase frizz and make porous hair feel rough. Chlorinated pools and frequent ocean swimming can also alter blonde, copper, and fashion shades.

Use a colour-safe cleanser, limit high heat, and protect the hair from direct sun when possible. A colour-depositing shampoo or conditioner can help maintain tone between services; this guide to colour depositing products explains how these formulas differ from oxidative colour.

Conditioning treatments should match the hair’s needs. Very porous lengths often benefit from a balance of moisture and occasional protein, while fine hair can become weighed down by heavy masks. If the hair feels gummy when wet, snaps during brushing, or stretches unusually far, pause further chemical processing and focus on repair.

Choose developer according to the result you need, not the strongest option available. Check the colour manufacturer’s mixing ratio, complete a patch and strand test, and work methodically from the regrowth or target area. When significant lightening or correction is involved, booking a qualified Australian colourist can protect both your hair and your final result.