Hair Color Filler: How to Dye Blonde Hair Brown Without Green, and When to Use a Color Remover

A hair color filler puts back the warm pigment that bleaching removed, before the hair is colored darker. It is needed when the hair is 3 or more levels lighter than the target: without it, dark color on blonde turns green or muddy, goes on unevenly and washes out fast. If the color has already come out wrong, the artificial pigment is removed: permanent color with an acid color remover, and with a bleach bath or lightener when the level has to come up along with the color. [1, 2]

Why use a hair color filler before a dark color?

Bleaching breaks down natural pigment in steps: red goes first, then orange, and light levels keep a yellow underlying pigment. Hair lifted from level 4 to level 8 loses all its red and orange pigment, and only yellow is left. The underlying pigment chart in the color wheel article shows the pigment of each level. [1]

Natural dark shades are made for hair that still has its warm pigment. If a cool dark color goes straight onto yellow blonde, the blue pigment of the dye mixes with the yellow:

“Blue + Yellow = Green… Not a very attractive result!”

— BCcampus

The second job of a filler is to even out porosity. Bleached hair absorbs color faster but also loses it faster, and when porosity differs from roots to ends, a dark color goes on unevenly. The filler evens out this difference before the main color. Hence the rule: if hair needs to go 3 or more levels darker, the filler comes first and the target color second; for 1–2 levels, the color goes on directly. [1]

For going darker, the developer is 1.5% (5 volume), mixed 1:1 with the dye. Bleached hair that needs to go 3–4 levels darker is colored after a filler or with a dense mix: 2 parts dye to 1 part 3% (10 volume) developer.

Hair color filler chart: which filler color to use

The BCcampus textbook for colorists gives a simple rule: hair is filled with the underlying pigment that lies 2 levels lighter than the target. If the target is level 4, the filler is level 6, and the underlying pigment of level 6 is orange, so a copper pigment is needed. After it, an ash level 4 dye gives a neutral dark color: the blue in the dye cancels the orange filler. [1]

Starting points for common targets; the filler color comes from the underlying pigment chart:

The colors in the table are each level's underlying pigment, not a specific dye number: the stylist picks the number in their own color line.

The filler does not always need neutralizing. For a warm or natural result, the copper and gold of the filler work for the color. For a cool result, the target dye needs ash pigment, which cancels the filler's warmth. [1]

There are two kinds of filler. The first goes on as a separate step, is processed and rinsed out before the target color; it is a semi-permanent or oxidative color chosen for the condition of the hair. The second is a liquid pigment with the target color applied right over it. [1]

Blonde to brown: 5 mistakes that turn hair green

1. An ash dark shade straight over blonde. The blue pigment of the dye lands on the yellow underlying pigment, and the hair turns green or khaki. [1]
2. Going 3 or more levels darker without a filler. The hair lacks the warm pigment the dark color is made for: the result is dull and muddy, and on porous areas the color washes out fast. [1, 2]
3. A cool target without ash pigment. The copper filler shows through the dye, and instead of a cool dark shade the result is copper. [1]
4. One formula for the whole length with uneven porosity. Porous ends take pigment faster, especially cool pigment, and come out darker and cooler than the mid-lengths. So the filler and the dye are chosen zone by zone. [1, 2]
5. Dark color over an over-toned blonde. A violet or blue toner shade under dark color gives a muddy tone. A filler with warm pigment cancels this shade first, and the dark color goes onto a neutral base. [1]

Color remover for hair: an acid remover or a bleach bath?

If the dark color has already come out wrong, the artificial pigment is removed. The first step is to find out what dye is on the hair. Direct dyes and semi-permanent color hold as large molecules in the cuticle. Permanent oxidative color is locked in as small molecules in the cortex. They are removed with different products. [2]

An acid color remover is gentler than lightener: it penetrates the cortex, shrinks the dye molecules and breaks their bonds, and then the molecules rinse out with water. They have to be rinsed out completely: the developer of the next step, in lightener or dye, develops the remaining molecules again, and the color partly comes back. A color remover cannot bring natural color back to bleached hair: pigment destroyed by bleaching does not return. [2]

An acid color remover does not remove direct dyes and semi-permanent color: they have their own products. These go only on the colored length, because on uncolored hair they also affect the natural pigment. Lightener over a direct dye slightly opens the cuticle and pushes the pigment deeper: the color comes out worse and shifts to another shade. [2]

A bleach bath removes an extra tone without changing the level or lifts the color 1–2 levels; it suits an over-toned blonde and weakened hair. Decolorizing with lightener removes the color of a previous coloring with a lift of 1–3 levels, in steps. Lift over artificial pigment is unpredictable: a mix of the underlying pigment and leftover dye shows through, a darker and warmer tone than on uncolored hair. So a strand test comes first, and after each step the color and the condition of the hair are assessed again. [2]

Mixes for color removal and lightening are made with lightener. A bleach bath is mixed with water or with developer, and the mix is emulsified on the hair. Decolorizing with lightener is done in steps, from a higher developer percentage to a lower one, wiping the hair down with a towel.

After color removal the hair is light and porous again. If it is colored dark again, the same rule applies: 3 or more levels darker means a filler first.

Frequently asked questions

Are a filler, pre-pigmentation and repigmentation the same thing?

A filler and pre-pigmentation, yes: in color manuals both words name putting warm pigment back before a darker color. Repigment usually means bringing color back to gray hair; in Russian color practice all three words mean the filler.

How do you get rid of a green tint after going darker?

Green is canceled with red: they are opposite colors on the color wheel. The stylist adds a dye with red or copper pigment. If the green is strong or the shade has to change, the artificial pigment comes out first, then the filler goes in and the hair is colored again.

Sources

The numbers in the text match the links below. Links checked on October 15, 2026.

1. BCcampus: tint back with a filler — § 7.2. The filler, the 2-level rule, porosity.
2. BCcampus: removing artificial color — § 7.3. Dye types, color removers, lightener with shampoo, the strand test.