?? ???? ???? ?????? ???? ?????? ?????? ???? ??? ?? ??? ????? ???????? ???? ??? ?????? ???? ??? ??? ??? ?????? ?? ??? ???? ?? ??????? ??? ???? ?????.Vat dyes are effectively insoluble in h2o and incapable of dyeing fibres instantly. Nevertheless, reduction in alkaline liquor creates the water-soluble alkali metallic salt of the dye.???? ???? ??? ???