ONE-PASS PIGMENT PRINTING OF BRIGHT COLORS ON A DARK TEXTILE BACKGROUND

When printing a coloured pattern over a dark textile background, the l atter shows through, since the coloured pigment and the binder are tra nsparent. An opacifier (titanium dioxide) can be added to hide the dar k ground, but this reduces the brightness of the pigment, so that red becomes pink, An opacifier has been found, diatomaceous earth (diatomi te), which has good hiding power for the dark ground, although not red ucing the colour strength of a coloured pigment mixed with it, allowin g the printing of bright colours. The colour strength of a red-pigment ed printing paste opacified with titanium dioxide increases slowly and linearly with pigment concentration. In contrast, when printing the r ed paste without opacifier on a white background, colour strength incr eases rapidly and then levels off at 3-4% pigment concentration. A dia tomite opacified paste behaves similarly, that is, like a coloured, tr ansparent medium applied to a white ground.