Effectual Parameters in Natural Dyeing:Dyeing of Woolen Yarns by Madder

According to the literature, it is possible to replace synthetic dyes with more echo-friendly natural dyes. One of the popular natural dyes in Iran is madder. This paper reports the effect of age and type of madder in natural dyeing process for better color behavior prediction. Effects of 4 different types of madder along with the role of the concentration and pH of dye bath are investigated. The amount of dye absorption is also evaluated by calculation of K/S value in the wavelength of minimum reflection. Samples are treated by using the classical aftertreatment process for natural dyes and the effect of aftertreatment on light and washing fastnesses of samples are reported. The CIELAB colorimetric specifications of samples are measured under D65 illuminant and 1964 standard observer. The light and washing fastnesses of dyed samples are also reported. Finally, the chemical structures of employed madders are studied by FTIR technique.