Criterion of Selecting Reactive Black Dyes Based on the Colorimetric Values

Abstract

Reactive dyes represent the biggest group of cotton dyes that can produce satisfying dye depths, excluding black tint. According to theoretical knowledge no group of dyes comprises a dye of black tint that would have colorimetric brightness values of L* < 0 and chromatic values of C* < 1. Based on practical experience and according to customer demands sulphur dye Diresul schwarz (black) RDT-2R meets the quality of black tint and was taken as standard for the purposes of this paper. The aim of the paper is to establish criteria by means of which black tints of the offered commercial dyes would be selected for industrial use. The following reactive dyes used in the industry were selected: Cibacron schwarz: F-2b, C-NN, LS-N and W-HF, Bezaktiv schwarz V-GRA and Remazol schwarz NF. Dyeing was carried out on cotton sorts from India, Israel and Malaysia. The dyed samples are defined with colouristic dye values and illustrated in a*/b*, C*/L*, dE and K/S diagram.