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How long should I leave in my bleach?


A very common question we always get about bleach is:

How long should I leave the bleach on the hair?

In this article, we will show you.

But first, we are going to explain to you how exactly bleach works.

How bleach works

The bleach and developer mix open up the hair cuticle.

The bleach mix then lifts out the melanin - the color molecules in the hair, in other words.

And the longer you leave it in, the more color molecules get lifted out.

And the lighter it gets.

Bleaching Levels

Now let's understand bleaching levels.

As you bleach, the hair typically starts to change color. 

You will start to see what colorists call undertones.

First you will see orange. This is when the hair is about level 6.

Then as you keep lifting, you will see orange-yellow.

Keep lifting and you will start to see bright yellow.

Lift some more again, and you will see very pale yellow.

When you see that, you know you have reached level 10.

This is where you need to take the hair to.

See the chart below.

Bleaching levels

Bleaching levels & undertones. 

How long should I leave the bleach in my hair?

The thing to understand about bleach is that as long as the mixture is moist, it will keep acting on the hair.

And it will keep lifting out color molecules.

Bleaching instructions sometimes say: bleach for 30 minutes.

But this is really just an average estimation.

To fine-tune what you need to do with your hair, you should apply your mixture, then wait 10 minutes.

Then peel back some of the mixture.

And check what level the hair has got to.

If after 10 minutes you are seeing copper or brassy yellow that means the hair is around level 6.

Realistically that means that the hair is not going to get to level 10 in 30 minutes.

At this point you need to make fresh bleach mix and reapply on all the sections which have not lifted enough.

(We will talk about developer strength later on, but when you make fresh mix and re-apply, incidentally, always use 20 Vol developer only.)

After 10-15 minutes, do this check again.

Hopefully by this time it should be approaching level 10.

Only rinse when it is indeed level 10 i.e. very very pale yellow.

What should the hair look like when I rinse?

Your aim as a colorist should be to get the hair to level palest yellow.

Either level 9 or ideally level 10.

The hair should look like in the pictures below.

Nothing else will do.

Level 10 hair

What Level 10 hair looks like rinsed and towel-dried

Level 9 hair wet and towel dried

What Level 9 hair looks like rinsed and towel-dried

Watch video: How long should I leave in my bleach?

I have applied my bleach mix but I am getting orange. What should I do?

Almost certainly you are doing something wrong. Let's go through all the possible things:

1. Make the right choice of bleach

What bleach did you use? Not all bleaches have the same lifting power and speed.

We really recommend you use a bleach that lifts fast.

Because the less time it sits processing on the hair, the better.

We really recommend you consider using Ugly Duckling bleaches.

They are renowned for their quality, and are some of the most fastest lifting bleaches on the market.

Brilliant Blondexx, our premium bleach, can be used on the root as well as lengths. It lifts up to 7 levels and contains Plex Technology.

Brilliant Blonde is our dust-free blue bleach and has been specially developed for dark bases. It lifts 8 levels.

Brilliant BlondexxBrilliant Blonde

Ugly Duckling Brilliant Blondexx & Brilliant Blonde

2. Make the right choice of developer

The rule is to use 20 vol developer for 1-2 levels and 30 vol developer or 3 levels of lift.

40 Vol is not required with good quality bleaches, unless you have some particularly tricky case of color correction.

3. Make your bleach mix correctly

The right mix is 1 part bleach to 2 parts developer.

Your bleach mix needs to be runny and moist. This will allow for good penetration of the mix into the hair.

Plus it will allow you to lift the hair fast, which is always good.

4. Get your application technique right

The hair needs to be literally drenched in the bleach mixture, otherwise it won't work well.

So section the hair finely and really whack on the mixture.

Start from the back for a full head bleach

Start on the root area when it's a regrowth application.

Then extend as appropriate.

5. Check & re-apply as necessary

Remember. It's a timing thing.

You need to be always looking at the hair and be ready to apply first on the parts that need it the most.

That way those parts get longer processing time than other parts.

For example, the ends may already be very white from previous bleaching applications.

You don't need to apply bleach there, and indeed you should not.

6. Leave the bleach for long enough

Under-processing the bleach in the hair is the most common mistake novice hairstylists make.

Don't be like that. Make sure you process the bleach mixture until you get to a level 9 or a level 10.

How should I apply the bleach mixture?

Always start applying at the part of the hair where it is darkest.

Very often this will be at the root or regrowth area, as in the picture below.

But in other cases (full head application on virgin hair, for example) you should start at the back of the hair.

That is where the hair is thickest. Then work your way around to the sides, where the hair is typically thinner.

I have a dark regrowth but the rest is white. What should I do?

Dark Regrowth

Ultra dark regrowth, white lengths.

In this case you would apply only on the dark part and nowhere else.

Otherwise you will get breakage.

If for some reason you have overlapped some of the bleach mixture onto the white, don't worry.

Just wipe back with a wet cloth to during processing time.

In the above case, you will really need to lift and lift until the roots are equal to the lengths before attempting to rinse.

Then at this point, when you tone, you would need to start where it is brassiest.

Probably that will be the root area which has just been lifted.

Then you would extend to the lengths at well, to brighten and tone those.

And to achieve consistency from roots to ends.

I have dark regrowth and orange lengths. What should I do?

Bleaching Drama

Dark regrowth, orange lengths.

In the above case, you would start on the regrowth area.

But after 10 minutes you would need to extend to the lengths which orange and also need lifting.

Then, when checking you would need to re-apply until the whole hair is consistent from root to ends.

That's the whole art of bleaching.

Once you get the whole head a consistent level 10, the toning will come out very well.

Once again, start toning where it is brassiest and then extend.

Should I use foil?

Using Foils and Heat

Using foil and indirect heat will help you speed up the lifting

Using foil is a great idea, because the foil keeps in the heat and will allow you to process the hair faster.

Using indirect heat is also good, and will do the same.

Remember, you still need to check after 10 minutes.

If the hair has not lifted enough, you will need to open up the foil and apply fresh mix.

How do you check whether the hair is lifting correctly?

You do this by peeling back the mixture and checking carefully.

The first check should be at 10 to 15 minutes after application.

A first check might show the hair looking like this.

If it does look like this, it means that hair has not lifted to level 10. You will need to do a fresh bleach application.

Incidentally, if you have been using foils, this is where the foil comes off.

You check, then you re-apply fresh mix straight onto the hair this time (20 Vol only, remember).

Peel Back hair

This hair is at level 8 and will need a fresh application of bleach

How do I know whether I should add in more bleach mixture?

If the hair is still at 9 or so, and it's been 15 minutes you need to keep processing it.

If the hair is darker than that at this stage (as in the picture above), you need to make a fresh mix and apply again.

Then re-check again after another 10-15 minutes.

The 30 minute rule is not a hard and fast rule.

Won't I break the hair if I bleach too long?

If at any stage it looks like the hair is losing its elasticity, or if you have reached very very pale yellow you need to rinse right away.

That is why the checking is so important as you bleach. You are checking lifting and hair quality both.

Check hair elasticity by pulling an individual hair strand and see whether it is stretching or not.

If it is stretching, that's good. It means that it is still elastic and that the integrity of the hair has been maintained.

What does this level look like?

But shouldn't I rinse after 30 minutes and bleach again?

It all depends.

In most cases, if it's a question of 10 more minutes, and the hair is still elastic, give it 10 more minutes.

But remember, the bleach won't lift if it is dry. So do think about re-applying fresh mix.

How do I tone the hair after bleaching?

Hair toned with Blondify

Hair toned with Blondify 010V after bleaching. Hair by Elona Taki

If you have done all our recommended steps correctly, the hair should be consistently very very pale yellow after bleaching and rinsing.

In which case we would suggest you use Blondify liquid toners.

They are ammonia-free, PPD-free, so very gentle to use and perfect for the hair after what has perhaps been a very strenuous bleaching session.

They only take 10 minutes to process.

And they are easy to apply because they are liquid.

How do I choose my toner?

Use the ash blonde toner if the hair is still on the brassy side.

Use the violet blonde toner if the hair is more on the yellow side.

You can also combine the 2 toners, do get both ash blonde and violet blonde toning in one go, as some hairdressers do.

Ash Toner

Natural Ash Blonde Toner

Natural Violet Blonde Toner

Natural Violet Blonde Toner

What developer should I use with my toner?

You can use with either 10 or 20 Vol developer. The mix ratio is 1+1. 

How should I apply it?

You can mix by shaking in an applicator bottle or in a coloring bowl, as you wish.

Then just pour over the hair and rub in very vigorously, so the entire head gets into contact with the toner.

Or apply with a brush, segmenting well if you are using a coloring bowl.

How can I maintain the whiteness of my blonde hair after bleaching and toning?

Purple Mask

Brilliant Blonde Purple Mask in use at a salon.

Use Brilliant Blonde Purple Shampoo and Mask.

And use Bond Protect Shampoo and Mask to strengthen and condition blonde and bleached hair.

Bond Protect Shampoo & Mask

Bond Protect Shampoo and Mask


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.

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