Each morning after the daily bath, an Ornatrix combed, crimped and styled her mistress' hair, using pins, hair nets and ribbons. Hair dyes are also applied at times; Pliny records a formula for black hair dye that included leeches and vinegar!
Some recipes for hair bleaching and dyeing suvive, and include a greasy formula called sapo from Germany to lighten the hair. Others included pepper, rat's heads, even excrement. It is reasonable to assume that these noxious formulae necessitated donning a wig for some poor souls.
Hairdressing followed, in general, contemporary Greek styles. From the latter part of the Republican era, however, coiffures became increasingly elaborate and often unbeautiful. It is said that in late Republican and Imperial times Roman women bleached and dyed their hair and, moreover, wore false blonde or red tresses taken from the heads of conquered northern barbarian women.
Characteristics of fashionable Imperial coiffures were: an excessive amount, frequently disposed in braids, intricately coiled; frizzing and curling; and high dressing in the front, either with frizzed hair, in the manner that we know as "pompadour," or with decorations of the diadem sort.
Note the diadem arrangement on the portrait bust of Marciana, (CE 95-117). The upstanding row of thick petals appears in to be metallic, though in other similar coiffures hair in tight cylindrical ringlets forms the diadem. A fringe of frizzed hair conceals a narrow band and a "beau-catcher" curl curves in front of the ear. The coiled braids are arranged in a great cap at the crown of the head, and the hair curls naturally and prettily in the nape. This is one of the more attractive styles.
Pretty, too, is a portrait bust of Julia Domna from the third century. Here her thick hair was marcelled and brought back low behind her neck; all the long back-hair is braided and interlaced in a basket-weave and pinned up at the back.
A veil was added at will to any Roman coiffure, often as a ritual accessory. As in Greek practice, this was draped loosely over head and shoulders, not, as a rule, bound to the head with a ribbon or circlet. Except with the veil and possibly, when travelling, with the petasos or sun-hat, or the cucculus, Roman women did not cover their hair.
Sources: I CLAVDIA : Women in Ancient Rome,