What developer volume and mixing ratio should you use for hair color

The ratio belongs to the product line

A mixing ratio is the amount of developer per part of color. It is not a setting you choose for each client. Each manufacturer writes it into the instructions for a specific line, and different lines from the same company can use different ratios.

Wella Professionals' instructions for Koleston Perfect permanent color read: 1 part Koleston Perfect hair color to 1 part Welloxon Perfect developer. L'Oréal Professionnel says to mix Majirel at 1 to 1.5, one 60 ml tube to 90 ml of its Oxydant developer. Wella's Blondor liquid toners are mixed 1 part toner to 2 parts 6 volume or 20 volume Welloxon Perfect, and its Blondor Multi Blonde lightening powder is mixed at 1:1.5 up to 1:2. Three common ratios, and all three can sit on the same salon shelf.

When you mix two shades from the same line, the ratio applies to the total amount of color. With 30 g of one shade and 30 g of another, you have 60 g of color, so a 1:1 line takes 60 g of developer and a 1:1.5 line takes 90 g. The instructions quoted here are written for mixing within one line, so check the manufacturer's guidance before combining lines.

What developer volume means

The volume number on a developer bottle stands for a strength of hydrogen peroxide, and manufacturers print the percentage alongside it. Wella sells Welloxon Perfect creme developer as 10 volume (3 percent), 20 volume (6 percent), 30 volume (9 percent) and 40 volume (12 percent), plus a 6 volume (1.9 percent) Pastel version. Its demi-permanent Color Touch uses its own emulsions at 6 volume (1.9 percent) and 13 volume (4 percent). L'Oréal Professionnel's Oxydant for Majirel comes in 12.5, 20 and 30 volume (3.75, 6 and 9 percent).

Volume is what controls lift. L'Oréal Professionnel's UK page for Majirel says 12.5 volume gives 1 to 1.5 levels of lift, 20 volume gives 2 levels and is the one used for covering white hair, and 30 volume gives 3 levels. Wella lists Koleston Perfect as offering up to 3 levels of lift.

Every line also sets a ceiling. L'Oréal Professionnel says Majirel is used with 30 volume at most. Wella says Blondor lightening powder applied on the scalp should be mixed with 20 volume or below. The 40 volume bottle exists, but that does not mean a given color or on-scalp service allows it.

Gray coverage and toning: where formulas change

Covering gray usually changes the shades in the bowl, not the ratio. L'Oréal Professionnel's Majirel instructions say that for up to 50 percent white hair you use the target shade alone, one 60 ml tube with 90 ml of 20 volume Oxydant. For 50 to 100 percent white hair with cool reflects, you mix half a tube of the target shade with half a tube of a natural base shade, still with 90 ml of Oxydant; for warm reflects, the second half is a golden base shade instead. The ratio stays at 1 to 1.5 throughout.

Toners and demi-permanent color run on short, tightly defined times. Wella's Blondor liquid toner instructions give up to 10 minutes for pastel toning and up to 30 minutes for base toning, checking frequently. Schwarzkopf Professional says Igora Vibrance demi-permanent color develops for up to 20 minutes, with 10 to 20 minutes for global and regrowth applications and 5 to 20 minutes for a gloss.

Mixing and testing at the bowl

Manufacturers write ratios in parts and sometimes in milliliters, as L'Oréal Professionnel does with its 60 ml tube and 90 ml of developer. Whichever unit you use, measure color and developer the same way. Weighing both on a scale in grams keeps the amounts precise and easy to write down.

Mix just before you apply. The label on Wella's Welloxon Perfect developer says to use the mixture immediately and discard anything left over, not to leave mixed color in a closed applicator bottle because the bottle may expand or burst, not to use a metal bowl or stirrer, and not to exceed the stated development time.

Test the skin first. The US Food and Drug Administration advises a patch test on the skin every time before hair is dyed. Wella's Koleston Perfect label asks for a skin sensitivity evaluation before each coloring for every client, and says not to color anyone who has reacted to hair color before or to a temporary black henna tattoo.

This is general product information, not medical advice. A client who has had a reaction to hair dye should follow the product warnings and talk to a doctor.

Common developer mistakes

Treating the ratio as a lift control. Brands set the ratio per line and describe lift by developer volume; L'Oréal Professionnel's chart for Majirel gives different lift for 12.5, 20 and 30 volume, all at the same 1 to 1.5 ratio. Adding extra developer to a 1:1 line moves the mix away from the instructions the product was written for.

Swapping developers between brands. Wella's developer label says it is to be used in combination with Wella Professionals hair color and lighteners, and L'Oréal Professionnel says Majirel is to be used exclusively with its own Oxydant. The ratio in each set of instructions assumes the matching developer.

Recording only the shade. A note that says which shade you used cannot be repeated, because the same shade at a different volume or time gives a different result. Write down the brand, line, shade codes, grams of each shade, developer volume, ratio and processing time while they are in front of you.

Doing the arithmetic in your head. Totals are easy to get wrong with gloves on and a client waiting. ColorCarte lists a formula as lines of brand, shade and grams, totals the color, and fills in the developer amount at 1:1, 1:1.5 or 1:2, whichever ratio you pick, with fields for developer volume and processing time on the same visit.

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