Indigo Carmine Food colour is completely a mixture of disodium 3,3' disodium 3,3' dioxo - 2,2' -bi-indolylidene-5,5' - disulfonate, - dioxo-2,2' - bi-indolyldene-5,7' –disulfonate, subsidiary coloring matters along with sodium chloridesodium sulfate as main uncolored component. The Indigo Carmine Color food color is insoluble in water. It is also known as Acid Blue