A process for treating keratin fibres may include applying a hair treatment composition to the keratin fibres. The composition may comprise at least one of fatty substances, surfactants, polymers with a glass transition temperature (Tg) ranging from about 40° C. to about 150° C., oxidation dye precursors, and direct dyes. The process may also include inserting the keratin fibres into a device comprising two elements that are moveable relative to each other between an open position and a closed position. In the closed position, the two elements may define a substantially leaktight closed space. The process may further include moving the two elements into the closed position to confine the keratin fibres in the closed space, and heating the keratin fibres to a temperature ranging from about 40° C. to about 250° C. while the keratin fibres are confined in the closed space.本発明は、ケラチン繊維、特に毛髪を処置する方法であって、- 脂肪性物質、界面活性剤、40～150℃のTgを有するポリマー、酸化染料前駆体および直接染料から選択される少なくとも1種の化合物を含む毛髪処置用組成物を、ケラチン繊維に適用し、- ケラチン繊維を、開放位置および閉鎖位置の間を相互に可動であり、実質的に漏れのない閉じられた空間を画定する2つの要素を含む装置に挿入し、- ケラチン繊維を実質的に漏れのない空間内に閉じ込めるように2つの可動要素を共に閉鎖位置まで持っていき、- 繊維を40～250℃の温度まで加熱する、方法に関する。
