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Home / Blog/ Which developer strength should I use? - Complete Guide for Colorists
Home Blog Which developer strength should I use? - Complete Guide for Colorists

Which developer strength should I use? - Complete Guide for Colorists


1. What Is Developer & What Exactly Does it Do?

Developer or Activator is a essentially hydrogen peroxide in a cream base. It is an essential element in any coloration involving permanent hair color and bleaching process.

The hydrogen peroxide opens the hair cuticle. It also combines with the permanent hair color or bleach and helps activate it. Thanks to the developer and color combination, the following three things take place:

  • The hair cuticle gets opened so that the color pigments can penetrate it.
  • The natural color molecules (the hair melanin, in other words) and also molecules from previous color applications get lifted out
  • New color pigments get delivered and get inserted into the cortex of the hair.
  • Once installed, the color molecules swell, develop and expand and ultimately become a permanent part of the hair shaft.
  • Once installed correctly thanks to developer, the color is essentially permanent.
  • You will only need to worry about regrowth

In addition to the above, the developer + color combination also does the following:

  • Softens coarse hair and adds body to fine hair. 
  • Alters the internal body of the hair fiber permanently. 

Which is why hair oftentimes feels softer stronger and thicker after a coloring - provided of course, that it has been done right.

2. How Should I Choose the Right Strength of Developer?

  • If you want to get the best result, it is absolutely important that you choose the right strength of developer.
  • The right choice of developer strength can determine whether you lift the hair enough or not, and whether you achieve a high quality "3D" color result with correct vibrancy and intensity.
  • And very crucially, whether you preserve the quality of your or your client's hair.
  • The strength of developer is expressed in percentage (%) or units of volume (Vol.). The higher the number is the stronger the developer is and it therefore more lightens hair.
  • Always check your client's hair color level and compare it to the level you are trying to achieve. The difference is the number of levels that you are trying to lift, and this will determine developer choice (and also whether you need to pre-lighten with bleach or not).

3. Which Strength of Developer Should I use When Using Hair Color?

  • For level on level coloring, or coloring darker, use 10 Volume developer (3% peroxide)
  • For 1- 2 level lift, use 20 Volume developer (6% peroxide)
  • For 2-3 levels lift, use 30 Volume developer (9% peroxide)
  • For greater than 3 levels lift, pre-lighten with bleach and developer and follow these rules for bleach & developer mix:

4. Which Strength of Developer Should I use With my Bleach? 

  • For up to 3 levels lift, use bleach with 20 Vol developer.
  • For greater than 3 levels lift, use bleach with 30 Vol developer.
  • For second time bleach applications, use only 20 Vol developer otherwise you will damage the hair excessively.
  • For the root area, also use 20 Vol unless the hair is really really dark.
  • Once the hair has been lightened correctly, you should only need to use 20 Vol developer with your color.
  • Basically, 30 Vol should only be used once, and preferably on the lengths and not on the root area.

5. Which Strength of Developer Should I use when covering Grey Hair? 

  • For any grey hair application, use 20 Volume developer (6% peroxide).
  • Grey hair needs extra softening to open up.
  • Also, in the case of salt and pepper hair when going blonde, the "pepper" part needs to be lifted up otherwise it will always stick out.
  • Hence 20 Volume developer is what you should use for grey hair coverage, not 10 Volume (as is sometimes taught in cosmetology classes).

6. Which Strength of Developer Should I use when toning the hair blonde? 

  • For toning with Ugly Duckling toners, we recommend that you use 20 Volume developer (6% peroxide)
  • Ugly Duckling toners are built to give lift and vibrancy. They work best with 20 Vol. developer.

7. Which Strength of Developer Should I use when using high lift colors? 

  • Ugly Duckling high lift colors will give up to 5 levels lift.
  • Use these with 30 Vol developer.

8. Should I use the same brand of Developer as my hair color or bleach? 

  • Of course we do recommend Ugly Duckling developers - their quality and freshness is impeccable.
  • However, as long as you use a cream based developer which is fresh.
  • If the brand of developer does not clearly mark its date of manufacture and sell-by date, that is not a good sign.
  • Also make sure that your developer has not been not left opened or in a hot place - exposure to heat will degrade its lifting capability.
  • It is more important that you choose the right brand of color and bleach as these vary a lot in exact color result and lifting capability.
  • So don't compromise on these - and save money on your developer if you wish!

9. How about previous colorations?

  • Hair that has had color deposited into it will be harder to lift than virgin hair.
  • In particular, hair that has been colored black or dark with box dye is notoriously difficult to remove.
  • Henna hair, metallic dyed hair is also difficult to remove.
  • So are (paradoxically) some semi-permanent colors. Which are oftentimes not semi-permanent at all.
  • These colors work by staining the surface of the hair and can be very stubborn.
  • In such cases you would need to bump up the developer choice by one level.

10. How about Porous hair? Which strength of developer should I use?

  • Porous hair is easily lifted and it absorbs the color very well. But the color will fade quickly.
  • Very often it is the ends which are porous, whereas the roots and mid-lengths are in much better condition.
  • Very often these porous ends are blonde anyway.
  • So if you are trying to go lighter and the ends are blonde and porous you should use a lower volume developer or shorten the processing time at the ends by only applying in the last 5-10 minutes or so.
  • When darkening porous ends, you would need to use the regular volume of developer to ensure better penetration of color pigments.

11. I need to lift a lot & I don't want to use bleach. Is it OK to use 40 Vol developer with my color instead?

  • It is not recommended. 40 Vol developer swells up the hair cuticle so much it risks blowing it apart permanently.
  • You would be better off using a quality bleach which lifts well. Use the bleach with 20 Vol or 30 Vol. developer as indicated in part 4 above.
  • Then use your color with 20 Vol. developer.
  • You will get much better results that way.

12. I bleached my hair with 30 Vol and my hair is still orange. Should I use the bleach with 40 Vol developer?

  • What bleach were you using?
  • All bleaches are not the same and some beauty store bleaches in particular have very poor lifting properties.
  • Using a poor quality bleach with 40 Vol developer? That's asking for trouble.

About the author

Sally has been a hair colorist and trainer for many years in both the US & Europe. She currently does hair color training for Ugly Duckling. She also helps develop new & awesome products for the brand.