Prussian Blue Hue (PBk9, PB15:0, PV23) is one of three new historical colors recently added to our High Flow line. ⁠ ⁠ True Prussian Blue (PB27) is one of the first synthesized pigments and this deep, nearly black color is alkaline sensitive so it cannot be made into an acrylic paint. Our modern mixture in acrylics provides a similar color with very good permanence. ⁠ ⁠ Have you tried this color yet?