Level 4 hair color: medium brown

Level 4 is medium brown, and the shade at this level that causes more trouble than all the others put together is the ash. So this page starts with the pigment the ash was made for, goes through the reds that ride on it, and only then gets to lifting, gray and the codes.

What a 4 looks like

Medium brown is brown in every light. A 3 passes for black indoors; a 4 never does. At the window it is a mid brown, warm on the ends and cooler at the root, and self-described light brown is nearly always a 4 with sun on the ends, which is why the number gets read at the first inch of root and nowhere else. It is the most common natural level in a color chair across most of Europe and the Americas. Colored, a 4N is a deep neutral brown and a 4.3 a chestnut, both richer on a level 4 head than the swatch, because the hair’s own depth adds to the deposit.

The red-orange under it, and the ash built for it

The pigment at level 4 is red-orange. Lift a 2 into a 4 with 20 vol, or a 1 with 30 vol, and red-orange comes up to meet the shade, so a 4 formulated as if the hair were white lands warmer than planned. Lift a 4 through its own level and it keeps moving: orange-red at 5, orange at 6, yellow-orange at 7, yellow at 8. The chart’s stages match the manufacturers’ charts, and the head is usually a level more orange than the chart at whatever point the lift stalls, so the strand you scrape and dry is the one to formulate from. Blue-green cancels red-orange; that is what an ash shade at this level is. Too much and the brown goes khaki, then a flat green-gray that looks dusted, and any ash reads darker than the natural at the same number, since cool tones give back less light.

4.1 is ash, and the shade that generates the most panicked messages. It cancels the red-orange that lift exposes: on a natural 4 with 20 vol a little warmth comes up, the ash meets it, and the result is a cool, quiet brown. On 10 vol over a natural 4, deposit only, nothing warm has been exposed for the green to cancel, so it sits on a neutral brown and tips it khaki. On lengths lightened last year and toned back down, it goes plainly green. A working rule is half 4.1 and half 4N for a whole head, a quarter 4.3 in it if the hair is porous, and straight 4.1 only as a five-minute gloss on ends throwing orange.

4.5 and 4.6, the reds that use the pigment

4.5 is mahogany, red-violet on brown. On a 4 it reads as a deep burgundy-brown in daylight and plum in shade, the violet cooling the hair’s own orange while the red rides on top. 4.6 is red, a red-brown that reads as auburn at this depth, and the most forgiving shade at level 4 because it heads the same direction as the pigment underneath. Both fade toward warm, which is why a client who leaves a mahogany for eight weeks still looks colored rather than grown out.

Lifting a 4

From a natural 4 the developer sets the distance: 20 vol reaches a 6, 30 vol a 7, and a high-lift series on 40 vol reaches an 8, on virgin hair only. Past that it is lightener, 20 vol on the scalp and 30 in foils, in rounds of fresh mix with a bond builder in the bowl. Whichever way the lift goes, mids and ends go on first and the root last, because the scalp is hot and the first inch runs ahead of the rest; a bright first inch on an otherwise even head is a hot root, and it comes from the scalp’s heat and from the root going on too early. A natural 4 who wants a 7 lands on a warm 7 with yellow-orange showing, and a blue-violet toner takes it to the blonde in the picture. The toner goes on at that level or darker, on 10 vol or the brand’s own 5 to 9 vol toning developer, and it moves the tone and never the level.

Coarse hair at 4 can sit at 6 under 30 vol and refuse to go further, and fine hair can shoot past, which no chart predicts, so a test section through the full time before the whole head is how one visit or two gets quoted. And a 4 that came out of a box for three years is a different job: permanent color moves natural pigment only, so 30 vol lifts the regrowth to a warm 7 and leaves the lengths at 4. For that head it is a color remover and a re-read, or lightener on selected pieces and a gold gloss at 6 or 7, and the question about box dye gets asked at every consultation, twice if the answer comes too fast.

Gray on a 4

The natural series does the covering. Fashion shades at level 4 cannot hold white hair on their own, so under 50 percent gray use half N, and over it the N straight, on 20 vol, since 10 vol only blends. White hair takes a 4N at the full depth of the tube, since there is nothing underneath it. A regular with about 40 percent gray at the front might run half 4N, half 4.3, 20 vol, 35 minutes, unchanged for two years, with the front going on first and getting the longest time and an extra ten minutes when the white is stubborn. Regrowth at this level shows at three to four weeks. The gray coverage calculator gives the split for any percentage.

Getting to 4 from either side

From a 2 it is two levels: 20 vol, 30 on coarse or resistant hair. From a 1, three levels, so 30 vol or a high-lift with 40 vol on virgin hair. From a 5 or 6 it is deposit, 10 vol demi or 20 vol permanent for coverage. From a 7 or lighter on lightened hair, three levels or more, fill first with a warm 5 or 6, gold or copper, to put the red-orange back, then the 4 on 10 vol. Skip the fill and the 4 goes muddy. On a lifted head that only needs to be a 4 again at the root, a shadow root of 4N demi smudged into the first inch does the job with less commitment and grows out without a line. The level chart gives the lift for any pair, the developer mix calculator turns a ratio into grams, and level 5 is the next step up.

The shades at level 4

The codes read the same way in every line, level first and tone after, and mean slightly different things in each, so 4A in one brand is 4.1 in another and the ash inside it is blue in one and green in the next.