Êtes-vous un étudiant de l'EPFL à la recherche d'un projet de semestre?
Travaillez avec nous sur des projets en science des données et en visualisation, et déployez votre projet sous forme d'application sur Graph Search.
Concept
Henna
Résumé
Henna is a dye prepared from the plant Lawsonia inermis, also known as the henna tree, the mignonette tree, and the Egyptian privet, and one of the only two species of the genus Lawsonia, with the other being Lawsonia odorata.
Henna can also refer to the temporary body art resulting from the staining of the skin using dyes from the henna plant. After henna stains reach their peak color, they hold for a few days, then gradually wear off by way of exfoliation, typically within one to three weeks.
Henna has been used since antiquity in ancient Egypt and Indian subcontinent to dye skin, hair and fingernails, as well as fabrics including silk, wool, and leather. Historically, henna was used in West Asia including the Arabian Peninsula and in Carthage, other parts of North Africa, West Africa, Central Africa, the Horn of Africa and the Indian subcontinent.
The name henna is used in other skin and hair dyes, such as black henna and neutral henna, neither of which is derived from the henna plant.
The word henna comes from the Arabic (ALA-LC: ḥinnāʾ; pronounced ħɪnˈnæːʔ).
Whole, unbroken henna leaves will not stain the skin because the active chemical agent, lawsone, is bound within the plant. However, dried henna leaves will stain the skin if they are mashed into a paste. The lawsone will gradually migrate from the henna paste into the outer layer of the skin and bind to the proteins in it, creating a stain.
Since it is difficult to form intricate patterns from coarsely crushed leaves, henna is commonly traded as a powder made by drying, milling and sifting the leaves. The dry powder is mixed with one of a number of liquids, including water, lemon juice, strong tea, and other ingredients, depending on the tradition. Many artists use sugar or molasses in the paste to improve consistency to keep it stuck to the skin better. The henna mix must rest between one and 48 hours before use in order to release the lawsone from the leaf matter. The timing depends on the crop of henna being used.
Source officielle
À propos de ce résultat
Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.