Colorimetric properties of wool dyed with Cochineal: Effect of Dye-bath PH

In the present work an evaluation was carried out on the effect dye-bath pH and mordant type on the obtained shades and fastness properties in wool dyeing with cochineal. In this way wool samples were first mordanted with four different mordants and subsequently dyed with cochineal at different levels of dye-bath pH. Colorimetric evaluations were carried out and fastness properties of the dyed samples were assessed. Changes in chemical structure of the dye in different pH conditions was also discussed. It was found that the pH of dye-bath has a great effect on obtained shades. Based on the results, combination of dyeing in different levels of dye-bath pH along with mordanting with various mordants can considerably develop the range of obtainable hues in dyeing of wool with cochineal. The fastness properties of the dyed samples in different conditions were also studied.