Levels average. Tones do not.
Take each shade's level, multiply by its grams, add the two and divide by total grams: 40 g of a level 7 with 20 g of a level 5 gives (7 × 40 + 5 × 20) ÷ 60 = 6.33, a level 6 on its lighter side. But do it in your head once before you trust the tile.
Tone is a direction on the color wheel, and directions do not average; they add up, soften each other or cancel, depending on how far apart they sit, so the second tile gives a description where you expected a number.
Tones are directions, not amounts
Picture each tone digit as an arrow. Natural has no arrow. Gold points at yellow, copper at orange, red at red, mahogany at red-violet, violet at violet, ash at blue-green. Beige (.13 or .21) is a short arrow, yellow with some blue in it, already a compromise.
Arrows pointing the same way keep the tone; the grams set its strength. Neighbors add up to something between. Arrows across the wheel cancel, more the nearer to opposite. Hair color is the only branch of chemistry where "what do I get if I mix these" is so often answered with "brown".
| Pair | What you get | Worth mixing? |
|---|---|---|
| N + any tone | A softer version of that tone | Yes, the safest mix |
| Ash .1 + Gold .3 | Sandy beige | Yes, home-made .13 |
| Violet .2 + Gold .3 | Neutral beige, pearl | Yes, classic toner logic |
| Ash .1 + Violet .2 | Pearl at level 8 and up; smoky at 7; muddy at 6 and below | Only on light hair |
| Gold .3 + Copper .4 | Warm apricot | Yes |
| Copper .4 + Red .6 | Hot red-orange | Yes |
| Red .6 + Violet .2 | Burgundy, a cool red | Yes |
| Ash .1 + Copper .4 or Red .6 | Neutral brown; the tones cancel | No, buy the brown |
| Violet .2 + Copper .4 | Dusty rose-brown; neither survives | Rarely |
| Beige .13 + anything | The partner's direction, softened | Yes |
For two years clients asked for my beige by name. It was 8.1 and 8.3 at 2:1. Two parts ash to one part gold, 40 g and 20 g in the bowl. (Nobody reads the tube, so nobody asked. In fourteen years, perhaps three people have looked at the ratio on it.) The ratio did the work. At 1:1 the pair is the plain sand above, and the extra ash tipped it into the cooler, slightly gray beige people kept photographing in bathroom mirrors, under the worst light in the house.
Where the average lies to you
The level sum assumes every gram carries the same dye load. It does not. A level 4 tube holds far more pigment than a level 9, because it has to deposit a darker result, so mix a 4 with an 8 and the 4 wins by more than the grams say: half a level darker than the sum, a full level when the gap is wide.
I learned that with 5N and 8N at 30 g each.
She wanted a 6 and a half. The sum said 6.5. The hair said 5.5 at best. It cost her a second appointment and me ninety minutes of a Saturday with a color remover; the 8 had done little beyond thinning the 5.
Purpose is the second problem. A level 8 permanent is built to lift to 8 and deposit an 8 tone. Half and half with a 4 it has neither the pigment nor the developer share to do either, so what comes out is a 4 or 5 with a sheerer finish, and the calculator flags any gap over two levels for that reason. It cannot tell you how heavily a line loads its dark shades; some 5s mix like a 4.5, and the only way I know is a strand test or a year on that line.
Developer follows the color total: 60 g of mixed color at 1:1 takes 60 g of developer, and the volume still decides lift, as the level chart lays out. Two shades from one line share a ratio and a base; two from different lines may not, and then the ratio is wrong for one of them whatever you do, so both my tubes come from one line.
When to mix and when to just buy the shade
In my chair, I think a custom mix earns the second tube about one time in three: an intensity the tube does not offer; an in-between level when the shades sit within two levels; a pair that reinforces itself; a beige made on purpose. The rest of the time the first tube already had it; plenty of colleagues would put that figure higher.
Buy the shade when:
- the tones cancel. A mixed brown is a worse brown than the one in the tube, and it cost two tubes;
- the level gap is three or more;
- the job is gray coverage. The natural series is built for it and the gray coverage calculator works out how much N a formula needs;
- the batch is bigger. The developer mix calculator turns any color total into developer grams for your ratio.