Abstract: The formula of computer measuring and matching color was deduced, and the basic database of the color cotton base fabrics was established. The blank cotton fabrics were dyed by single dye once and twice, and their total amount of dye were same. The results showed that the K/S values of cotton fabrics ,were dyed twice, were lower than once. According to this phenomenon, the existing overdyeing function was questioned. Basic databases of the blank cotton base fabrics and the color cotton base fabrics were established respectively, and the accuracy of this database was tested. The results showed that the K/S value of dye concentration per unit, obtained from the basic database of the color cotton base fabrics directly, was more suitable for the overdyeing process of color cotton fabrics. As a result, the overdyeing number was reduced and the overdyeing time was decreased. The theory of computer measuring and matching color was expanded to a certain extent according to actual situation and provided a new method of color cotton fabric overdyeing for the application of computer measuring and matching color in this paper.

Key words: colored xotton fabric , substrati fabric , computer color meaduring and matching , overdyeing