Wella T18 Toner is one of Wella’s lightest shades. It is made to cancel pale yellow and help you get a clean ash blonde.
Wella recommends using a 20-volume developer with their T18 toner. But if you already have a stronger one, like 30 volume or 40 volume, you may wonder if you can use it.
Quick Answer
- Do not use 30 or 40 volume with Wella T18. It can over process bleached hair and irritate the scalp.
- Use 20 volume as the standard option, or 10 volume for gentler deposit.
- T18 only works well on light hair (level 9 – 10). If your hair is orange or dark yellow, pick a different toner or lighten your hair again safely.
Can You Use Wella T18 Toner With a 30-Volume Developer?
No. Do not use a 30-volume developer with Wella T18. It is too strong for pre-bleached hair and can cause breakage and scalp irritation. Wella T18 is made for hair that is already very light.
Follow the manufacturer’s directions for developer strength and timing when you dye, tone, or bleach your hair.
As stated on the Wella T18 package, the recommended mixing ratio is two parts 20-volume developer to one part Wella T18 toner. However, if you want a gentler color correction, you can use 10-volume developer.
Using a stronger developer like 30-volume can lead to uneven tone, extra warmth, dryness, and snap-prone hair.
Do not leave toner on longer than the directions say. For Wella T18, that is up to 30 minutes. Check every few minutes. Overprocessing can dull the result and weaken the hair.
What Happens if You Use a 30-Volume Developer with T18 Toner?
A stronger developer is made to lift color. For example, if you use a 30-volume developer with permanent color, it can lift the base while it deposits.
But Wella T18 is different. It is meant for hair that has already been bleached to a very light level. Adding high-strength peroxide can push the hair past its limit. That can lead to rough texture, breakage, and patchy tone.
It also will not fix darker brass. If your hair is still orange or deep yellow, stronger peroxide will not make T18 “work harder.” It may just lift unevenly and damage your hair.
Can I Dilute 30-Vol and 40-Vol Developer to 20-Vol Developer and Use It With T18 Toner?
Yes, but the safest choice is to buy the correct 20-volume developer. If you must dilute, use distilled water only. Do not dilute with conditioner for this process because it can make results less predictable.
WARNING
The safest and easiest choice is to buy the correct volume developer. Diluting developer with water makes the mixture much runnier. That means it can drip into your eyes. It can also spread onto hair you did not mean to lighten. If you still dilute, measure with accuracy, apply with extreme care and wear golves and eye protection.
To dilute 30 volume down to about 20 volume, mix two parts 30-volume developer with one part distilled water.
Example: 100 ml of 30 vol + 50 ml water = 20 vol
To dilute 40 volume down to about 20 volume, mix one part 40-volume developer with one part distilled water.
Example: 100 ml of 40 vol + 100 ml water = 20 vol
Measure carefully. Do not try to mix water without accurate measurement, as it will change volume to an unknown percentage. So, buying a 20-volume developer is easier and safer.
Why Does Toner Need a Developer to Work?
A developer helps open the hair cuticle so pigment can get inside the hair shaft. Without a developer, most permanent toners will not process correctly and can sit on the surface.
If you don’t use a developer when applying toner, the cuticle stays more sealed and the result may be weak or uneven.
How To Use Toner With Developer
With Wella T18, stick to 20 volume as the standard option. If you want a gentler deposit and less stress on the hair, use 10 volume. Never use 30 or 40 volume with this toner.
Unless the brand says otherwise, toner is often mixed at two parts developer to one part toner. For T18, follow Wella’s directions.
Apply to clean, towel dried hair. Focus on the brassy areas first. Avoid rubbing the mixture into your scalp.
Process up to 30 minutes, or less if you only need a small shift. Rinse well, then shampoo and condition.
Which Neutralizing Toner Should I Use?
Different brass levels need different toners. The key is to match the toner level to your hair level. If you are unsure, this guide can help: which neutralizing Wella toner should you use?
Wella T18 is best for very light hair with pale yellow tones. Think level 10.
If you have underlying orange or dark yellow tones, T18 is usually too light. You may need a different shade, such as a deeper ash toner, or a safer round of lightening before toning.
If you have red-orange or deep orange undertones in brown hair, you may need blue-green toning.
You may need green toning for dark red undertones in very dark hair.
Toner Treatments Versus Color Shampoos
A toner treatment is mixed with a developer and works fast. That is why developer choice matters so much with very light, bleached hair.
Color shampoos are slower but gentler. Purple shampoos can help maintain a pale blonde between toning sessions. Blue shampoos can help with orange tones.
If your hair is very porous or fragile, a color shampoo may be a safer first step than another strong chemical service.
Why Does Dyed Hair Need Toner?
Sometimes color looks too warm, too dull, or not even. Toner helps refine the shade so it looks cleaner and more natural.
Why Does Bleached Hair Need Toner?
Bleached hair can turn orange instead of platinum, even when you follow the steps. Dark pigments can be hard to lift fully in one session.
After bleach, leftover warm pigments can show through. Toner helps cancel that warmth, but only if the hair is light enough for the toner level.
How Long Do I Leave in Toner T18 and Developer Mix on Hair?
T18 toner and developer can be left on for up to 30 minutes. You can rinse sooner if you only need a small amount of toning.
High-volume developer can damage hair fast, especially on bleached lengths. That is why you should stick to 20 volume or 10 volume for this toner.
Wrapping Up
Using T18 with high-strength developer is a bad idea. Stick with 20 volume, or 10 volume for a gentler deposit.
If you only have 30 or 40 volume, you can dilute it with distilled water to reach about 20 volume. Measure carefully, or buy the correct developer. Always follow the manufacturer’s directions when you dye, tone, or bleach your hair.