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How Long Should I Leave Wella T18 Toner in My Hair?

Cute white girl with bleached blonde hair with light yellow tones.

Wella T18 toner can transform your color-treated hair from a brassy mess to the beautiful ashy blonde hair you’ve always wanted, but only if you use it correctly.

One of the biggest questions people have when using this toner is, “How Long Should I Leave Wella T18 Toner in My Hair?” The truth is that it depends.

As annoying as that answer may be, we’ll clear everything up for you in this article. By the end, you’ll know how long to leave Wella toner on your hair, factors affecting the recommended processing time, and more! 

How Long Do You Leave Wella T18 On Your Hair?

You can leave Wella T18 Toner on your hair for up to 30 minutes. Wella Color Charm uses a 1:2 mix ratio, one part toning color, and two parts 20 volume developer. Apply the toner to dry hair for up to 30 minutes, frequently checking for the desired color result.

Leave the toner on for approximately 8-10 minutes for lighter hair and up to 20-30 minutes for darker hair. This toner removes “brass” for perfect blonde hair. To achieve the best results, you should lighten your hair before applying the toner.

The Instructions on the Wella T18 Toner Packaging

Natural blonde white female with type 1a towel-dried hair wearing a white t-shirt with flowers.

When determining how long to leave Wella T18 on your hair, the first step is to look at the instructions on the packaging. But it’s important to understand that these instructions will not get everyone the desired results.

They are generalized and should be tweaked to suit the individual. If you review the instructions on the toner, they’ll say that you should leave the toner on for up to 30 minutes.

The “up to” portion suggests that you can leave it on for less than 30 minutes when appropriate. They also state that you should check your hair frequently to determine when you’ve achieved the proper level of toning. 

So, according to the instructions, we can glean that the maximum amount of time to leave Wella T18 on your hair is 30 minutes. However, if you leave it on for 30 minutes, your hair may get over toned, so let’s dive a bit deeper into this.

Factors Affecting Wella Toner Processing Times

Dark blonde female used Wella toner to create ash blonde shade light hair color.

Many things affect how long you should leave Wella T18 on your hair, including how brassy your hair is and the condition of your hair.

In the below sections, we’ll explore each of these and what it means for your toner processing time. 

How Brassy or Warm Your Hair Is

In case you weren’t aware, Wella T18 toner should only be used after you’ve bleached your hair to a level 9 (the palest yellow) or lighter, according to the Wella toner chart.

Due to variations in hair types and bleaching results, your hair at a level 9 could look different in terms of warmness and brassiness than someone else’s. That’s why 30 minutes of toner processing will not work for everyone. 

If your hair is super brassy, you should leave the toner on your hair for closer to 30 minutes. This will give the toner enough time to open your hair shaft and deposit the pigment completely.

If your hair is only a bit brassy, leave it on for closer to 15 minutes. If you leave it on for longer than you need to, you could end up with over toned, gray hair. 

The Condition of Your Hair

After bleaching your hair to a level 9, it may be highly porous, dry, and even crunchy. If this is the case, you shouldn’t compound the damage with a long toning session.

While Wella T18 toner is nowhere as damaging as bleach, it does contain ammonia, which alters the hair’s pH and lifts the cuticle.

Any product that lifts your hair cuticles can be damaging – now imagine raising your cuticles after blasting them open with bleach. It’s a recipe for disaster. 

In addition, the porosity of overbleached or damaged hair can cause the toner to take unevenly. This can lead to an uneven, unattractive result.

For the above reasons, if your hair is not in the best shape post-bleaching, you’ll want to leave the toner in your hair for as short a time as possible – about 10 to 15 minutes.

Remember that the time suggestions referenced here are generalized. You should always check your hair during processing to make sure that you get the results you desire. 

Also, if you are making a dramatic change in your hair color, you will increase the likelihood of experiencing hair damage. For example, going from dark brown hair (or dark hair in general) to a very light blonde shade is a significant change.

If you’re in this situation, we recommend checking your hair frequently to ensure that your naturally dark hair isn’t damaged beyond repair.

Hair Toner, Over toned Hair and How to Fix It

Lady wearing a black dress, eye shadow, blush, and pink lipstick with golden brassy hair.

Over-toned hair is a nightmare that you should avoid like the plague. It can totally ruin your hair, causing it to look grey and muddy.

It’s often caused by leaving toner in your hair for too long. You may get over toned hair if you leave Wella toners on your hair for longer than 30 minutes or on severely compromised hair. 

There are a few ways that you can fix over toned hair: 

  • Wash it– The least damaging way to fix over-toned hair is to wash it a few times with your favorite shampoo. You may find that this is all you need to reduce the unsightly dark or gray tones in your hair. If you have red tones, orange tones, or yellow tones, read this article to understand how to neutralize unwanted orange or yellow tones.
  • Try clarifying shampoo – If washing your hair with your regular shampoo didn’t work, up the ante with clarifying shampoo. It cleanses deeper and will remove more of the unwanted toner than typical shampoo. 
  • Bleach it (last resort)- As a last resort, if nothing else worked, and your hair isn’t totally fried, you can use bleach. Here are the steps to follow: 
  • Prepare the bleach according to the instructions on the bleach container. Use a 20 volume developer for this to minimize the damage to your hair. 
  • Apply protective cream to the skin around your hairline and apply the bleach to your hair. Start at the ends and move up toward the roots. If you have just a couple of problem areas, focus the bleach on those areas.
  • Allow the bleach to process for about 5 to 10 minutes and then rinse it out. 

*We urge you not to do all of this in one day or even over the course of a few days. Give your hair a break between potentially harsh treatments.

Also, bleaching your hair after toning it could leave you with some leftover brassiness that you’ll need to get rid of with another toning session. 

If you were hoping to get platinum blonde hair and ended up with orange hair, read the previously linked article correcting over-toned hair.

Do a Strand Test

White girl with a nice warm blonde hair shade with smoky black eyes.

To take the guesswork out of toning, do a strand test on your bleached hair. Immediately after bleaching, mix up a little bit of toner (Wella T18 + 20 volume developer) and apply it to a tiny section of your hair.

Leave it on for the recommended 30 minutes or less if you’d like, and then check your results. If your hair still appears brassy after processing, you should leave it in for longer. Reduce the time you leave it on if your hair turns gray.

When you do the strand test, you should also put a bit of the toner on your skin to see whether it’ll result in a skin reaction. It’s better to be safe than sorry! 

How to Check Your Results While Toning

Pretty white girl with a naturally blonde shirt boy cut hairstyle.

To get the best hair toning results, you need to monitor your progress as you tone. It’s pretty easy to do, but if you’ve never done it before, you may need some guidance. Here are the steps to follow: 

  1. After applying the toner, wait for 5 to 10 minutes. 
  2. Choose a small section in the back of your head and wipe away the toner. You could also rinse the toner off of the section and then towel dry your hair, though it will take a bit more time.
  3. Look at the section of hair very closely to observe whether the brassiness is gone. 
  4. If not, reapply the toner and allow your hair to continue processing. 
  5. Repeat steps 2 through 4 to check again if you’d like. 

With the information presented in this article, you have everything you need to get perfectly toned hair using Wella T18 toner.

If you have questions, we recommend that you reach out to a local stylist or Wella directly. We hope that this article is helpful to you as you experiment with at-home toning!