What exactly is developer?
Developer is, quite simply, hydrogen peroxide. Different companies will include different additives but at a base level the hydrogen peroxides job is to lift the cuticle layer of the hair. The stronger the developer the more the cuticle opens and the more lightening of natural pigment it has.
Volumes and Uses:
5 volume is becoming a more used developer but often teamed with semi and demi-permanent colour lines for its minimal effect on the cuticle and deposit only. The hair will no longer be virgin and it will shift the natural shade a very small amount, however, it will not offer grey coverage or lift. Its role is as an activator for the color and will typically be in developers specifically made for glazes and toners.
Pro-tip: When used with bleach, 5 volume can create a very slight shift in the hair, which is great for fragile baby hairs needing only 1-2 levels of lift.
10 volume will slightly open the cuticle and allow for moderate penetration of color molecules. Similar to 5 volume, 10 volume can be used with permanent color lines for depositing color, however, it will not offer much grey coverage or lift. If the hair is a finer fabric it could over a slight one level lighter shift in base color and grey blending. 10 volume is also the default developer for many toners and glazes, however, keep in mind that this higher volume developer means a possible shift to the natural base color. When 10 volume is used with bleach it can give 1-4 levels of lift depending on the bleach, the method of application, and the hair.
20 volume is likely the most used developer in the salon. 20volume will give 1-2 levels of lift when used with permanent hair color. It is the standard developer for grey coverage, however, a stronger developer may be needed for more resistant hair types. 20 volume should not be used as a developer for toner or glazes especially when wanting to maintain a natural base. When used with bleach, 20 volume is a powerful tool lifting 1-9 levels depending on the bleach, method of application, and hair type/history. 20 volume is the highest level of developer that should be used on the scalp with bleach as the scalp produces more heat and increases the power of the developer.
30vol developer is ideal for lifting 3 levels using permanent hair color depending on the texture and natural depth of the hair. It can also be used for grey coverage on more resistant hair types. When used with bleach and foils 30 volume works fast and may incur the risk of over-processing. This developer is more ideal for open-air processing.
40vol developer can be used with permanent hair color and high lift color to give 4-5 levels of lift depending on the power of the color and the texture of the hair. We don’t recommend using 40vol with bleach.
Does it really matter if I used the same developer as the color or can I use a generic developer?
Since the primary active ingredient of a developer is hydrogen peroxide any developer should work with most any color line. HOWEVER, many color lines spend years formulating a specific developer to best work with their color formula and thus lift, tonality, longevity and consistency can only be guaranteed when using the ideal partner products. With Eva Professional colour being a cross between gel and cream, we have developed a lighter textured liquid/cream developer to give our product a creamy, silky texture during application. It ensures the cuticle opens and delivers gentle colour into the cortex of the hair. We always recommend using our developer with Eva colour.
Pro-tip: because our colour is softer in texture, using our developer will make your colour go further. If you use a thicker developer the colour will be thicker and have less penetration of the cuticles.
Lastly, measure the amount of developer required as per the manufacturers instructions. Measuring the correct amount ensures better coverage of grey hair, better longevity of the colour and the correct levels of lightening. Never guess, even if you are an experienced colourist. A baker doesn’t guess the amount of flour to put in a cake, they will weigh, no matter how many times they’ve made cake before!